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Which of the following contains a vague pronoun reference?
[ "Alice and her husband met Jill for lunch at a small café around the block from her office.", "Alice and her husband met Jill for lunch at a small café around the block from Jill's office." ]
0
closed choice
grade11
language science
writing-strategies
Pronouns
Identify vague pronoun references
When writing, make sure to avoid vague pronoun references. A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent. When Lisa and Kim finally landed, she breathed a sigh of relief. The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear. Vague pronoun references can be corrected in one of two ways: 1. Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief. 2. Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed. A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent. They say that this nail polish dries in less than five minutes. The pronoun they is used without its antecedent, so the meaning of the sentence is unclear. This problem can be fixed by replacing the pronoun with its missing antecedent. The advertisements say that this nail polish dries in less than five minutes.
The second answer choice contains a vague pronoun reference. The pronoun her could refer to Alice or Jill. The first answer choice shows a possible correction for the vague pronoun reference. Her has been replaced with Jill's. Alice and her husband met Jill for lunch at a small café around the block from Jill's office.
Using only these supplies, which question can Danny investigate with an experiment?
[ "Do toy cars go faster down the ramp made of wood or the ramp made of cardboard?", "Does a big toy car go down the wooden ramp faster than a small toy car?", "Do toy cars with plastic wheels go faster down the cardboard ramp than toy cars with metal wheels?" ]
0
Danny and his sister are building ramps to race their toy cars down. Danny notices that the cars go down some of the ramps faster than others. He wonders what factors affect the cars' speed. So, he decides to design an experiment. He has the following supplies available: two identical toy cars a wooden ramp three feet long and two feet tall a cardboard ramp three feet long and two feet tall
closed choice
grade7
natural science
science-and-engineering-practices
Designing experiments
Identify questions that can be investigated with a set of materials
Experiments can be designed to answer specific questions. When designing an experiment, you must identify the supplies that are necessary to answer your question. In order to do this, you need to figure out what will be tested and what will be measured during the experiment. Imagine that you are wondering if plants grow to different heights when planted in different types of soil. How might you decide what supplies are necessary to conduct this experiment? First, you need to identify the part of the experiment that will be tested, which is the independent variable. This is usually the part of the experiment that is different or changed. In this case, you would like to know how plants grow in different types of soil. So, you must have different types of soil available. Next, you need to identify the part of the experiment that will be measured or observed, which is the dependent variable. In this experiment, you would like to know if some plants grow taller than others. So, you must be able to compare the plants' heights. To do this, you can observe which plants are taller by looking at them, or you can measure their exact heights with a meterstick. So, if you have different types of soil and can observe or measure the heights of your plants, then you have the supplies you need to investigate your question with an experiment!
Using only these supplies, which question can Kamal investigate with an experiment?
[ "Do rubber balloons stick to a wooden door or a metal door longer after being rubbed on his hair?", "Do rubber balloons or foil balloons stick to the wooden door longer after being rubbed on his hair?", "Do rubber balloons stick to a cotton blanket or a wooden door longer after being rubbed on his hair?" ]
2
Kamal went to a magic show. The magician rubbed a balloon on her hair and then held the balloon against a wall. When the magician released the balloon, Kamal was amazed to see that it stuck to the wall! He wonders what factors affect how well balloons stick to different surfaces. So, he decides to design an experiment. He has the following supplies available: the hair on his own head a cotton blanket a wooden door five rubber balloons
closed choice
grade8
natural science
science-and-engineering-practices
Designing experiments
Identify questions that can be investigated with a set of materials
Experiments can be designed to answer specific questions. When designing an experiment, you must identify the supplies that are necessary to answer your question. In order to do this, you need to figure out what will be tested and what will be measured during the experiment. Imagine that you are wondering if plants grow to different heights when planted in different types of soil. How might you decide what supplies are necessary to conduct this experiment? First, you need to identify the part of the experiment that will be tested, which is the independent variable. This is usually the part of the experiment that is different or changed. In this case, you would like to know how plants grow in different types of soil. So, you must have different types of soil available. Next, you need to identify the part of the experiment that will be measured or observed, which is the dependent variable. In this experiment, you would like to know if some plants grow taller than others. So, you must be able to compare the plants' heights. To do this, you can observe which plants are taller by looking at them, or you can measure their exact heights with a meterstick. So, if you have different types of soil and can observe or measure the heights of your plants, then you have the supplies you need to investigate your question with an experiment!
What information supports the conclusion that Russell acquired this trait?
[ "Russell learned biology by doing experiments.", "Russell is most interested in plant biology." ]
0
Read the description of a trait. Russell knows a lot about biology.
closed choice
grade3
natural science
biology
Heredity
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment.
What is the volume of a soda bottle cap?
[ "10 liters", "10 milliliters" ]
1
Select the better estimate.
closed choice
grade5
natural science
units-and-measurement
Units and measurement
Choose metric units of volume
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Volume is a measurement of how much space something takes up. There are many different units of volume. When you are using metric units, volume may be written in units of milliliters or liters. There are 1,000 milliliters in 1 liter. So, 1 milliliter is much less than 1 liter. A raindrop has a volume of about 20 milliliters, while a large soda bottle has a volume of 2 liters. The flask shown here measures volumes up to 500 milliliters.
The better estimate for the volume of a soda bottle cap is 10 milliliters. 10 liters is too much.
Which sentence states a fact?
[ "Bananas taste great with melted chocolate.", "Bananas turn yellow as they become ripe." ]
1
closed choice
grade3
language science
writing-strategies
Opinion writing
Distinguish facts from opinions
A fact is something that can be proved to be true. The month of July has more days than the month of June. This is a fact. It can be proved by looking at a calendar and counting the number of days in each month. An opinion is something that a person believes, thinks, or feels. An opinion cannot be proved true. July is a better month than June for camping. This is an opinion. People may have different opinions about which month is "better" for camping.
The first sentence states a fact. Bananas turn yellow as they become ripe. It can be proved by observing bananas as they ripen. The second sentence states an opinion. Bananas taste great with melted chocolate. Great shows what a person believes, thinks, or feels. Another person might have a different opinion about how bananas with melted chocolate taste.
Select the living thing.
[ "cat", "house" ]
0
closed choice
grade3
natural science
biology
Classification
Identify living and nonliving things
All living things need food and water. Water helps living things break down food and remove waste. Food gives living things energy. Living things use this energy to grow and change. All living things grow and change during their lives. All living things sense changes in the world around them. Living things might sense changes by seeing, smelling, hearing, or feeling. Living things can respond to the changes they sense.
A cat is a living thing. Cats grow and respond to the world around them. They need food and water. A house is not a living thing. Houses do not have all of the traits of living things. They do not grow or respond to the world around them. They do not need food or water.
Which correctly shows the title of a poem?
[ "\"About the Teeth of Sharks\"", "\"about the teeth of Sharks\"" ]
0
closed choice
grade4
language science
capitalization
Formatting
Capitalizing titles
In a title, capitalize the first word, the last word, and every important word in between. The Wind in the Willows James and the Giant Peach These words are not important in titles: Articles, a, an, the Short prepositions, such as at, by, for, in, of, on, to, up Coordinating conjunctions, such as and, but, or
Capitalize the first word, the last word, and every important word in between. The words the and of are not important, so they should not be capitalized. The correct title is "About the Teeth of Sharks."
Based on this information, what is this pea plant's phenotype for the pod shape trait?
[ "constricted pods", "dd" ]
0
This passage describes the pod shape trait in pea plants: In a group of pea plants, some individuals have inflated pods and others have constricted pods. In this group, the gene for the pod shape trait has two alleles. The allele D is for inflated pods, and the allele d is for constricted pods. A certain pea plant from this group has constricted pods. This plant has two alleles for constricted pods.
closed choice
grade8
natural science
biology
Genes to traits
Genetics vocabulary: genotype and phenotype
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.
An organism's phenotype for a trait is its observable version of that trait. The pea plant's observable version of the pod shape trait is constricted pods. So, the plant's phenotype for the pod shape trait is constricted pods.
What information supports the conclusion that Fred acquired this trait?
[ "Fred learned how to build a fire at summer camp.", "Fred can cook food over a fire." ]
0
Read the description of a trait. Fred knows how to build a fire.
closed choice
grade3
natural science
biology
Heredity
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment.
Is a toothbrush a good or a service?
[ "a service", "a good" ]
1
closed choice
grade2
social science
economics
Economics
Goods and services
Everything you can buy is either a good or a service. A good is something you can touch or hold in your hands. For example, a hammer is a good. A service is a job you pay someone else to do. For example, cooking food in a restaurant is a service.
To decide whether a toothbrush is a good or a service, ask these questions: Is a toothbrush something you can touch? Yes. Is a toothbrush a job you might pay someone else to do? No. So, a toothbrush is a good.
Complete the sentence. Cesar Chavez came from () family.
[ "an African American", "a Mexican American", "a Chinese American", "a French American" ]
1
closed choice
grade3
social science
us-history
Historical figures
Cesar Chavez
Cesar Chavez came from a Mexican American family: His father's parents were from Mexico. They moved to the United States in 1880. Cesar Chavez's father was born in Arizona. Cesar Chavez's mother was born in Mexico. She and her family moved to Arizona when she was six months old. Cesar Chavez was born in the United States in 1927. During Cesar Chavez's life, he and many other Mexican American people were treated unfairly because of their heritage. Cesar Chavez worked to fight this unequal treatment.
Suppose Tommy decides to plant the gardenias. Which result would be a cost?
[ "Tommy will give up the chance to look at the palm tree. He thinks it would have looked more beautiful than the gardenias.", "He will save some space. The gardenias will use up less space than the palm tree would have used up." ]
0
Tommy is deciding whether to plant gardenias or a palm tree in his backyard. He wants to make his backyard more beautiful. But he also wants to leave space for doing fun things.
closed choice
grade5
social science
economics
Basic economic principles
Costs and benefits
Before you decide to do something, it is often helpful to list costs and benefits. Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need. Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Tommy wants or needs: Tommy will give up the chance to look at the palm tree. He thinks it would have looked more beautiful than the gardenias.
Based on this information, what is Madelyn's phenotype for the Thomsen disease trait?
[ "not having Thomsen disease", "having Thomsen disease" ]
1
This passage describes the Thomsen disease trait in humans: In a group of humans, some individuals have Thomsen disease and others do not. In this group, the gene for the Thomsen disease trait has two alleles. The allele for not having Thomsen disease (m) is recessive to the allele for having Thomsen disease (M). Madelyn is a human from this group. Madelyn has the homozygous genotype MM for the Thomsen disease gene.
closed choice
grade8
natural science
biology
Genes to traits
Genetics vocabulary: dominant and recessive
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait. Some traits, like flower color in pea plants, are controlled by a single gene. Most plants and animals have a genotype made up of two alleles for these traits. These two alleles determine whether an organism is homozygous or heterozygous for the gene. An organism with two identical alleles for a gene is homozygous for that gene. A pea plant with the genotype FF or ff is homozygous for the flower color gene. An organism with two different alleles for a gene is heterozygous for that gene. A pea plant with the genotype Ff is heterozygous for the flower color gene. The types of alleles in an organism's genotype determine the organism's phenotype. Some alleles have types called dominant and recessive. These two types can cause different versions of a trait to appear as the organism's phenotype. A dominant allele causes its version of the trait to appear even when the organism also has a recessive allele for the gene. In pea plants, the F allele, which causes purple flowers, is dominant over the f allele. A pea plant with at least one F allele will have the F allele's version of the flower color trait. So, a plant with the genotype FF or Ff will have purple flowers. A recessive allele causes its version of the trait to appear only when the organism does not have any dominant alleles for the gene. In pea plants, the f allele, which causes white flowers, is recessive to the F allele. A pea plant with only f alleles will have the f allele's version of the flower color trait. So, a plant with the genotype ff will have white flowers.
Madelyn's genotype for the Thomsen disease gene is MM. Madelyn's genotype of MM has only M allelles. The M allele is for having Thomsen disease. So, Madelyn's phenotype for the Thomsen disease trait must be having Thomsen disease. To check this answer, consider whether Madelyn's alleles are dominant or recessive. The allele for not having Thomsen disease (m) is recessive to the allele for having Thomsen disease (M). This means M is a dominant allele, and m is a recessive allele. Madelyn's genotype of MM has two dominant alleles. An organism with at least one dominant allele for a gene will have the dominant allele's version of the trait. So, Madelyn's phenotype for the Thomsen disease trait must be having Thomsen disease.
Using only these supplies, which question can Lisa investigate with an experiment?
[ "Do squash plants grow larger if the seeds are planted with compost or without compost?", "If squash seeds and tomato seeds are planted with compost, which type of plant grows larger?", "Do squash plants grow larger if the seeds are planted in small pots or in large pots?" ]
0
Lisa has a small vegetable garden, which includes a compost pile of food scraps. She notices that some of the squash plants growing next to the compost pile grow differently than squash plants that are farther away. She wonders what factors affect how her squash plants grow. So, she decides to design an experiment. She has the following supplies available: one type of squash seeds four large clay pots soil a compost pile water
closed choice
grade7
natural science
science-and-engineering-practices
Designing experiments
Identify questions that can be investigated with a set of materials
Experiments can be designed to answer specific questions. When designing an experiment, you must identify the supplies that are necessary to answer your question. In order to do this, you need to figure out what will be tested and what will be measured during the experiment. Imagine that you are wondering if plants grow to different heights when planted in different types of soil. How might you decide what supplies are necessary to conduct this experiment? First, you need to identify the part of the experiment that will be tested, which is the independent variable. This is usually the part of the experiment that is different or changed. In this case, you would like to know how plants grow in different types of soil. So, you must have different types of soil available. Next, you need to identify the part of the experiment that will be measured or observed, which is the dependent variable. In this experiment, you would like to know if some plants grow taller than others. So, you must be able to compare the plants' heights. To do this, you can observe which plants are taller by looking at them, or you can measure their exact heights with a meterstick. So, if you have different types of soil and can observe or measure the heights of your plants, then you have the supplies you need to investigate your question with an experiment!
Which ball of clay has more thermal energy?
[ "the hotter ball of clay", "the colder ball of clay" ]
0
Two 200-gram balls of clay are identical except for their temperatures.
closed choice
grade6
natural science
physics
Thermal energy
How are temperature and mass related to thermal energy?
Matter is made of tiny particles called atoms. Atoms are always moving. The energy of moving atoms is called thermal energy. The total amount of thermal energy in matter depends on three things: the type of matter, the amount of matter, and how fast the atoms are moving. Temperature measures how hot or cold matter is. If the atoms in matter move faster, the temperature goes up. The matter now has both more thermal energy and a higher temperature. What happens if the amount of matter changes? A 2-kilogram brick at 70°F has twice as much thermal energy as a 1-kilogram brick at 70°F. The two bricks have the same temperature, but the larger brick has twice as many atoms. So, it has twice as much thermal energy.
The two balls of clay are made of the same material and have the same mass. So, the hotter ball of clay has more thermal energy.
Which sentence states a fact?
[ "Olympic athletes are excellent role models for kids.", "The first modern Olympic Games were held in Athens in 1896." ]
1
closed choice
grade8
social science
civics
Social studies skills
Identify facts and opinions
A fact is something that can be proved true by research or observation. George Washington became president of the United States in 1789. This statement is a fact. It can be proved by researching what year George Washington was inaugurated president. An opinion is something that a person believes, thinks, or feels. An opinion can be supported by evidence, but it cannot be proved true. George Washington was a better president than Thomas Jefferson. This statement is an opinion. People can have different ideas about what makes someone a "better" president, so the statement cannot be proved.
The first sentence states a fact. The first modern Olympic Games were held in Athens in 1896. It can be proved by researching the history of the Olympics. The second sentence states an opinion. Olympic athletes are excellent role models for kids. Excellent shows what a person believes, thinks, or feels. Another person might have a different opinion about what makes a role model excellent.
What is the temperature of the air on a hot day?
[ "37°C", "37°F" ]
0
Select the better estimate.
closed choice
grade6
natural science
units-and-measurement
Units and measurement
Estimate temperatures
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Temperature can be written with units of degrees Fahrenheit (°F) or Celsius (°C). Use the list below to compare the two units. 212°F | Water boils | 100°C 98.6°F | Body temperature | 37°C 68°F | Room temperature | 20°C 32°F | Water freezes | 0°C
The better estimate for the temperature of the air on a hot day is 37°C. 37°F is too cold.
Compare the motion of three sailboats. Which sailboat was moving at the lowest speed?
[ "a sailboat that moved 50miles north in 10hours", "a sailboat that moved 75miles north in 10hours", "a sailboat that moved 35miles south in 10hours" ]
2
closed choice
grade3
natural science
physics
Force and motion
Compare the speeds of moving objects
An object's speed tells you how fast the object is moving. Speed depends on both distance and time. Distance tells you how far the object has moved. One unit used to measure distance is the mile. Time tells you how long the object has spent moving. One unit used to measure time is the hour. Think about objects moving for the same amount of time. The object that is moving the slowest will go the shortest distance in that time. It is moving at the lowest speed.
Look at the distance each sailboat moved and the time it took to move that distance. The direction each sailboat moved does not affect its speed. Notice that each sailboat moved for 10 hours. The sailboat that moved 35 miles moved the shortest distance in that time. So, that sailboat must have moved at the lowest speed.
Is the following trait inherited or acquired? Porter has a scar on his left ankle.
[ "acquired", "inherited" ]
0
closed choice
grade5
natural science
biology
Traits and heredity
Identify inherited and acquired traits
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits.
Children do not inherit their parent's scars. Instead, scars are caused by the environment. People can get scars after they get hurt. So, having a scar is an acquired trait.
According to Newton's third law, what other force must be happening?
[ "The gas pedal is pushing on Nina's foot.", "The gas pedal is pulling on Nina's foot." ]
0
Isaac Newton was born in the 1600s and studied how objects move. He discovered three fundamental laws about forces and motion. According to Newton's third law, for every force, there is an equal and opposite force. Consider the following force: Nina's foot is pushing on her car's gas pedal.
closed choice
grade6
natural science
physics
Velocity, acceleration, and forces
Predict forces using Newton's third law
According to Newton's third law, for every force, there is an equal and opposite force. This means that if one object is applying a force on a second object, the second object must also be applying a force on the first object, but in the opposite direction. For example, if your hand is pushing down on a table, the table is also pushing up on your hand. Or, if you are pulling forward on a rope, the rope is also pulling back on you.
Nina's foot is pushing on the gas pedal. So, Newton's third law tells you that the gas pedal is pushing on Nina's foot.
What information supports the conclusion that David acquired this trait?
[ "David's scar was caused by an accident. He cut his arm when he fell off his bicycle.", "Some scars fade more quickly than others." ]
0
Read the description of a trait. David has a scar on his right arm.
closed choice
grade3
natural science
biology
Heredity
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment.
What information supports the conclusion that Elizabeth acquired this trait?
[ "Elizabeth learned how to knit in an after school program.", "Elizabeth knits sweaters using cotton, wool, and other types of yarn." ]
0
Read the description of a trait. Elizabeth knows how to knit sweaters.
closed choice
grade6
natural science
biology
Genes to traits
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring.
Which word would you find on a dictionary page with the following guide words? neck - nobody
[ "nice", "nation" ]
0
closed choice
grade2
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on.
Put the words in alphabetical order. Since nice is between the guide words neck - nobody, it would be found on that page.
Is driving a taxi a good or a service?
[ "a good", "a service" ]
1
closed choice
grade2
social science
economics
Economics
Goods and services
Everything you can buy is either a good or a service. A good is something you can touch or hold in your hands. For example, a hammer is a good. A service is a job you pay someone else to do. For example, cooking food in a restaurant is a service.
To decide whether driving a taxi is a good or a service, ask these questions: Is driving a taxi something you can touch? No. Is driving a taxi a job you might pay someone else to do? Yes. So, driving a taxi is a service.
What do these two changes have in common? water evaporating from a lake cooking an egg
[ "Both are caused by heating.", "Both are caused by cooling.", "Both are chemical changes.", "Both are only physical changes." ]
0
closed choice
grade7
natural science
chemistry
Chemical reactions
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.
Step 1: Think about each change. Water evaporating from a lake is a change of state. So, it is a physical change. The liquid changes into a gas, but a different type of matter is not formed. Cooking an egg is a chemical change. The heat causes the matter in the egg to change. Cooked egg and raw egg are different types of matter. Step 2: Look at each answer choice. Both are only physical changes. Water evaporating is a physical change. But cooking an egg is not. Both are chemical changes. Cooking an egg is a chemical change. But water evaporating from a lake is not. Both are caused by heating. Both changes are caused by heating. Both are caused by cooling. Neither change is caused by cooling.
What do these two changes have in common? butter melting on a hot day baking a loaf of bread
[ "Both are caused by cooling.", "Both are only physical changes.", "Both are caused by heating.", "Both are chemical changes." ]
2
closed choice
grade8
natural science
chemistry
Chemical reactions
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.
Step 1: Think about each change. Butter melting on a hot day is a change of state. So, it is a physical change. The butter changes from solid to liquid, but it is still made of the same type of matter. Baking a loaf of bread is a chemical change. The type of matter in the dough changes when it is baked. The dough turns into bread! Step 2: Look at each answer choice. Both are only physical changes. Butter melting on a hot day is a physical change. But baking bread is not. Both are chemical changes. Baking bread is a chemical change. But butter melting on a hot day is not. Both are caused by heating. Both changes are caused by heating. Both are caused by cooling. Neither change is caused by cooling.
Which word would you find on a dictionary page with the following guide words? beetle - black
[ "bid", "back" ]
0
closed choice
grade4
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since bid is between the guide words beetle - black, it would be found on that page.
What do these two changes have in common? plants making food from sunlight, air, and water rust forming on a metal gate
[ "Both are caused by cooling.", "Both are caused by heating.", "Both are only physical changes.", "Both are chemical changes." ]
3
closed choice
grade4
natural science
chemistry
Physical and chemical change
Compare physical and chemical changes
Chemical changes and physical changes are two common ways matter can change. In a chemical change, the type of matter changes. The types of matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. When paper gets hot enough, it re­acts with oxygen in the air and burns. The paper and oxygen change into ash and smoke. In a physical change, the type of matter stays the same. The types of matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, ice melting is a physical change that can be caused by heating. Ice and liquid water are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.
Step 1: Think about each change. Plants making food is a chemical change. Plants use energy from sunlight to change air and water into food. The food is sugar. Sugar is a different type of matter than air or water. Rust forming on a metal gate is a chemical change. As the gate rusts, the metal turns into a different type of matter called rust. Rust is reddish-brown and falls apart easily. Step 2: Look at each answer choice. Both are only physical changes. Both changes are chemical changes. They are not physical changes. Both are chemical changes. Both changes are chemical changes. The type of matter before and after each change is different. Both are caused by heating. Neither change is caused by heating. Both are caused by cooling. Neither change is caused by cooling.
Read the following excerpt from a student essay. How can the writer best improve his or her grammar and mechanics? Self-expression is important, therefore, you should be yourself no matter what other people think. People might express their inner selves through music, art, or writing, through foods they eat, cook, and serve others, or through their home decor. I choose to express myself through my clothing and my hairstyle. When I was eight years old, my mother taught me how to sew, now I make all of my own clothes. I also dye my hair crazy colors, like green or blue. Sometimes people stare at me and seem to wonder why I look the way I do. My answer is, "I just gotta be me!"
[ "by adding missing commas", "by using semicolons correctly", "by punctuating the quotation correctly" ]
1
closed choice
grade11
language science
writing-strategies
Editing and revising
Suggest appropriate revisions
During peer review, you read and respond to a fellow student's writing. While there are many methods and strategies that you can use for reviewing a text, it is generally helpful to frame your suggestions in concrete and constructive ways and to consider the following areas for revision: Ideas and development: Does the writer express a clear idea and develop it with evidence, examples, or analysis? Organization: Does the writer order ideas in a clear, logical way so that they build on one another and are easy to follow? Voice: Does the writer maintain an appropriate voice, such as a formal and objective voice in an academic essay or an engaging and expressive voice in a narrative essay? Sentence fluency: Does the writer use sentences that vary in structure and length to create a sense of rhythm and flow within and between sentences, or does the writing sound choppy, rambling, or repetitive? Word choice: Does the writer use words accurately and precisely to create clear, effective, and engaging writing? Grammar and mechanics: Does the writer follow appropriate conventions, using accurate spelling, punctuation, and grammar to create writing that is correct and easy to read?
The writer could best improve his or her grammar and mechanics by using semicolons correctly. For example, the writer could use semicolons before the conjunctive adverb therefore in the first underlined sentence, to separate items in a series containing commas in the second underlined sentence, and instead of a comma to separate main clauses in the third underlined sentence. Self-expression is important, therefore, you should be yourself no matter what other people think. People might express their inner selves through music, art, or writing, through foods they eat, cook, and serve others, or through their home decor. I choose to express myself through my clothing and my hairstyle. When I was eight years old, my mother taught me how to sew, now I make all of my own clothes. I also dye my hair crazy colors, like green or blue. Sometimes people stare at me and seem to wonder why I look the way I do. My answer is, "I just gotta be me!"
Which correctly shows the title of a play?
[ "Big Bad and Little Red", "Big bad and Little Red" ]
0
closed choice
grade3
language science
capitalization
Formatting
Capitalizing titles
In a title, capitalize the first word, the last word, and every important word in between. The Wind in the Willows James and the Giant Peach These words are not important in titles: Articles, a, an, the Short prepositions, such as at, by, for, in, of, on, to, up Coordinating conjunctions, such as and, but, or
Capitalize the first word, the last word, and every important word in between. The word and is not important, so it should not be capitalized. The correct title is Big Bad and Little Red.
Suppose Raymond decides to take a trip to Rhode Island. Which result would be a cost?
[ "Raymond will spend more money. Plane tickets for Raymond to get to Rhode Island are more expensive than tickets to Illinois.", "Raymond will enjoy his trip to Rhode Island more than he would have enjoyed a trip to Illinois." ]
0
Raymond is deciding whether to take a trip to Rhode Island or Illinois. He wants to enjoy his trip. But he is also trying to save money.
closed choice
grade5
social science
economics
Basic economic principles
Costs and benefits
Before you decide to do something, it is often helpful to list costs and benefits. Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need. Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Raymond wants or needs: Raymond will spend more money. Plane tickets for Raymond to get to Rhode Island are more expensive than tickets to Illinois.
Which correctly shows the title of a movie?
[ "***That Thing You Do***", "\"That Thing You Do!\"" ]
0
closed choice
grade9
language science
punctuation
Formatting
Formatting titles
The title of a book, movie, play, TV show, magazine, or newspaper should be in italics. If you write it by hand, it can be underlined instead. A Midsummer Night's Dream The title of a poem, song, article, or short story should be in quotation marks. "You Are My Sunshine"
A movie should be in italics. The correct title is **That Thing You Do**.
How long is a paper clip?
[ "35 millimeters", "35 kilometers", "35 centimeters", "35 meters" ]
0
Select the best estimate.
closed choice
grade8
natural science
units-and-measurement
Units and measurement
Choose metric units of distance, mass, and volume
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. When you are using metric units, length can be written with units of millimeters, centimeters, meters, or kilometers. One meter contains 100 centimeters or 1,000 millimeters. So, 1 meter is larger than 1 centimeter, and 1 centimeter is larger than 1 millimeter. The tip of the pencil shown here is only 1 millimeter wide, but the pencil is about 16 centimeters long. A red fox is about 1 meter long. The Sydney Harbour Bridge in Australia is about 1,000 meters, or 1 kilometer, in length.
The best estimate for the length of a paper clip is 35 millimeters. 35 centimeters, 35 meters, and 35 kilometers are all too long.
Which tense does the sentence use? The cook will freeze the meat for another time.
[ "past tense", "present tense", "future tense" ]
2
closed choice
grade3
language science
verbs
Verb tense
Is the sentence in the past, present, or future tense?
Present tense verbs tell you about something that is happening now. Most present-tense verbs are regular. They have no ending, or they end in -s or -es. Two verbs are irregular in the present tense, to be and to have. You must remember their forms. Past tense verbs tell you about something that has already happened. Most past-tense verbs are regular. They end in -ed. Some verbs are irregular in the past tense. You must remember their past-tense forms. Future tense verbs tell you about something that is going to happen. All future-tense verbs use the word will. Present | Past | Future walk, walks | walked | will walk go, goes | went | will go
The sentence is in future tense. You can tell because it uses will before the main verb, freeze. The verb tells you about something that is going to happen.
Which is harder?
[ "metal horseshoe", "wool sweater" ]
0
closed choice
grade3
natural science
physics
Materials
Compare properties of materials
Every object is made of one or more materials. A material is a type of matter. Wood, glass, metal, and plastic are common materials. A material has different properties. A material's properties tell you how it looks, feels, tastes, or smells. Some examples of properties are shiny, hard, fragile, and stretchy. For example, a shiny material reflects a lot of light. A fragile material breaks when you drop it.
Hard is a property. A hard material keeps its shape when you press on it with your finger. Look at each picture, one at a time. Imagine pushing on the material shown in each picture. Of the choices, the metal horseshoe is harder. If you squeeze a metal horseshoe, it will not change shape.
Complete the sentence so that it uses personification. The butterflies flitted from flower to flower, ().
[ "playing hide-and-seek", "floating gently" ]
0
closed choice
grade10
language science
writing-strategies
Creative techniques
Use personification
Personification is giving human characteristics to nonhuman things. It is a figure of speech that can be used to make writing more interesting or to emphasize a point. The trees danced in the wind. The word danced describes the trees as if they were people. Unlike people, however, trees can't actually dance. Instead, the personification suggests that the trees are moving.
Complete the sentence with the phrase playing hide-and-seek. It describes the butterflies as if they were playful children.
Suppose Cameron decides to plant the amaryllises. Which result would be a cost?
[ "Cameron will give up the chance to look at the magnolia tree. He thinks it would have looked more beautiful than the amaryllises.", "He will save some space. The amaryllises will use up less space than the magnolia tree would have used up." ]
0
Cameron is deciding whether to plant amaryllises or a magnolia tree in his backyard. He wants to make his backyard more beautiful. But he also wants to leave space for doing fun things.
closed choice
grade5
social science
economics
Basic economic principles
Costs and benefits
Before you decide to do something, it is often helpful to list costs and benefits. Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need. Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Cameron wants or needs: Cameron will give up the chance to look at the magnolia tree. He thinks it would have looked more beautiful than the amaryllises.
Which figure of speech is used in this text? What thoughts I have of you tonight Walt Whitman, for I walked down the sidestreets under the trees with a headache self-conscious looking at the full moon. —Allen Ginsberg, "A Supermarket in California"
[ "antithesis", "apostrophe" ]
1
closed choice
grade11
language science
figurative-language
Literary devices
Classify the figure of speech: review
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Anaphora is the repetition of the same word or words at the beginning of several phrases or clauses. We are united. We are powerful. We are winners. Antithesis involves contrasting opposing ideas within a parallel grammatical structure. I want to help, not to hurt. Apostrophe is a direct address to an absent person or a nonhuman entity. Oh, little bird, what makes you sing so beautifully? Assonance is the repetition of a vowel sound in a series of nearby words. Try to light the fire. Chiasmus is an expression in which the second half parallels the first but reverses the order of words. Never let a fool kiss you or a kiss fool you. A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic. The head of Human Resources would never refer to firing people, only to laying them off. Hyperbole is an obvious exaggeration that is not meant to be taken literally. I ate so much that I think I might explode! An oxymoron is a joining of two seemingly contradictory terms. Some reviewers are calling this book a new classic. A paradox is a statement that might at first appear to be contradictory, but that may in fact contain some truth. Always expect the unexpected. Understatement involves deliberately representing something as less serious or important than it really is. As you know, it can get a little cold in the Antarctic.
The text uses apostrophe, a direct address to an absent person or a nonhuman entity. What thoughts I have of you tonight Walt Whitman is a direct address to Walt Whitman, an absent person. (Walt Whitman was an American poet who died in 1892, over half a century before this poem was written.)
Which organ uses acid to break down food?
[ "brain", "stomach", "muscles", "skin" ]
1
closed choice
grade5
natural science
biology
Animals
Human organs and their functions
Would you find the word did on a dictionary page with the following guide words? dangle - drank
[ "no", "yes" ]
1
yes or no
grade8
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since did is between the guide words dangle - drank, it would be found on that page.
Based on this information, what is Arietta's genotype for the fur texture gene?
[ "Ff", "straight fur" ]
0
In a group of Syrian hamsters, some individuals have straight fur and others have wavy fur. In this group, the gene for the fur texture trait has two alleles. The allele F is for straight fur, and the allele f is for wavy fur. Arietta, a Syrian hamster from this group, has straight fur. Arietta has one allele for straight fur and one allele for wavy fur.
closed choice
grade7
natural science
biology
Genes to traits
Genetics vocabulary: genotype and phenotype
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.
An organism's genotype for a gene is its combination of alleles for that gene. Arietta has one allele for straight fur (F) and one allele for wavy fur (f). So, Arietta's genotype for the fur texture gene is Ff.
What information supports the conclusion that Bonnie acquired this trait?
[ "Bonnie's friends like to make chili with her.", "Bonnie learned how to make chili from a recipe book.", "When Bonnie was young, her grandmother taught her how to cut chili peppers." ]
1
Read the description of a trait. Bonnie knows how to make chili.
closed choice
grade8
natural science
biology
Genes to traits
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring.
Which greeting is correct for a letter?
[ "Dear Uncle Aaron,", "Dear Uncle aaron," ]
0
closed choice
grade4
language science
punctuation
Formatting
Greetings and closings of letters
A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory
The second greeting is correct: Its first word is capitalized, and it ends with a comma. Uncle Aaron is capitalized because it is a proper noun.
What do these two changes have in common? baking a loaf of bread cooking a pancake
[ "Both are caused by cooling.", "Both are chemical changes.", "Both are only physical changes." ]
1
closed choice
grade3
natural science
chemistry
Physical and chemical change
Compare physical and chemical changes
Chemical changes and physical changes are two common ways matter can change. In a chemical change, the type of matter changes. The types of matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. When paper gets hot enough, it re­acts with oxygen in the air and burns. The paper and oxygen change into ash and smoke. In a physical change, the type of matter stays the same. The types of matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, ice melting is a physical change that can be caused by heating. Ice and liquid water are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.
Step 1: Think about each change. Baking a loaf of bread is a chemical change. Bread is made from dough. Baking turns the dough into bread. The bread is a different type of matter than the dough. Cooking a pancake is a chemical change. Pancakes are made from pancake batter. A cooked pancake is a different type of matter than pancake batter. Pancake batter is wet and slippery. Cooked pancakes are fluffy and can be good to eat! Step 2: Look at each answer choice. Both are only physical changes. Both changes are chemical changes. They are not physical changes. Both are chemical changes. Both changes are chemical changes. The type of matter before and after each change is different. Both are caused by heating. Both changes are caused by heating. Both are caused by cooling. Neither change is caused by cooling.
Suppose Eva decides to plant the tulips. Which result would be a cost?
[ "She will save some space. The tulips will use up less space than the hickory tree would have used up.", "Eva will give up the chance to look at the hickory tree. She thinks it would have looked more beautiful than the tulips." ]
1
Eva is deciding whether to plant tulips or a hickory tree in her backyard. She wants to make her backyard more beautiful. But she also wants to leave space for doing fun things.
closed choice
grade5
social science
economics
Basic economic principles
Costs and benefits
Before you decide to do something, it is often helpful to list costs and benefits. Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need. Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Eva wants or needs: Eva will give up the chance to look at the hickory tree. She thinks it would have looked more beautiful than the tulips.
Which of the following contains a vague pronoun reference?
[ "Bella had witnessed a crime, so she made a call to report it. They promptly dispatched police to investigate the scene.", "Bella had witnessed a crime, so she made a call to report it. The operator promptly dispatched police to investigate the scene." ]
0
closed choice
grade11
language science
writing-strategies
Pronouns
Identify vague pronoun references
When writing, make sure to avoid vague pronoun references. A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent. When Lisa and Kim finally landed, she breathed a sigh of relief. The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear. Vague pronoun references can be corrected in one of two ways: 1. Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief. 2. Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed. A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent. They say that this nail polish dries in less than five minutes. The pronoun they is used without its antecedent, so the meaning of the sentence is unclear. This problem can be fixed by replacing the pronoun with its missing antecedent. The advertisements say that this nail polish dries in less than five minutes.
The second answer choice contains a vague pronoun reference. The pronoun they is used without its antecedent. The first answer choice shows a possible correction for the vague pronoun reference. They has been replaced with the operator. Bella had witnessed a crime, so she made a call to report it. The operator promptly dispatched police to investigate the scene.
Based on this information, what is Hermes's phenotype for the coat pattern trait?
[ "a black coat", "a spotted coat" ]
1
In a group of jaguars, some individuals have a black coat and others have a spotted coat. In this group, the gene for the coat pattern trait has two alleles. The allele for a black coat (A) is dominant over the allele for a spotted coat (a). Hermes is a jaguar from this group. Hermes has the homozygous genotype aa for the coat pattern gene.
closed choice
grade6
natural science
biology
Genes to traits
Genetics vocabulary: dominant and recessive
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait. Some traits, like flower color in pea plants, are controlled by a single gene. Most plants and animals have a genotype made up of two alleles for these traits. These two alleles determine whether an organism is homozygous or heterozygous for the gene. An organism with two identical alleles for a gene is homozygous for that gene. A pea plant with the genotype FF or ff is homozygous for the flower color gene. An organism with two different alleles for a gene is heterozygous for that gene. A pea plant with the genotype Ff is heterozygous for the flower color gene. The types of alleles in an organism's genotype determine the organism's phenotype. Some alleles have types called dominant and recessive. These two types can cause different versions of a trait to appear as the organism's phenotype. A dominant allele causes its version of the trait to appear even when the organism also has a recessive allele for the gene. In pea plants, the F allele, which causes purple flowers, is dominant over the f allele. A pea plant with at least one F allele will have the F allele's version of the flower color trait. So, a plant with the genotype FF or Ff will have purple flowers. A recessive allele causes its version of the trait to appear only when the organism does not have any dominant alleles for the gene. In pea plants, the f allele, which causes white flowers, is recessive to the F allele. A pea plant with only f alleles will have the f allele's version of the flower color trait. So, a plant with the genotype ff will have white flowers.
Hermes's genotype for the coat pattern gene is aa. Hermes's genotype of aa has only a alleles. The a allele is for a spotted coat. So, Hermes's phenotype for the coat pattern trait must be a spotted coat. To check this answer, consider whether Hermes's alleles are dominant or recessive. The allele for a black coat (A) is dominant over the allele for a spotted coat (a). This means A is a dominant allele, and a is a recessive allele. Hermes's genotype of aa has only recessive alleles. An organism with only recessive alleles for a gene will have the recessive allele's version of the trait. So, Hermes's phenotype for the coat pattern trait must be a spotted coat.
What is the mass of an elephant?
[ "4,115 kilograms", "4,115 grams" ]
0
Select the better estimate.
closed choice
grade5
natural science
units-and-measurement
Units and measurement
Choose metric units of mass
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Mass is a measurement of how much matter something contains. There are many different units of mass. When you are using metric units, mass may be written with units of grams or kilograms. There are 1,000 grams in 1 kilogram. So, 1 gram is much less than 1 kilogram. A paper clip has a mass of about 1 gram, while a textbook has a mass of about 1 kilogram.
The better estimate for the mass of an elephant is 4,115 kilograms. 4,115 grams is too light.
What kind of sentence is this? Reagan considers Paris the most romantic city in the world.
[ "interrogative", "exclamatory", "declarative" ]
2
closed choice
grade9
language science
punctuation
Sentences, fragments, and run-ons
Is the sentence declarative, interrogative, imperative, or exclamatory?
There are four kinds of sentences. A declarative sentence is a statement and always ends with a period. The nurse told Mr. Abrams to roll up his sleeve so that she could check his blood pressure. An imperative sentence makes a request or a demand and usually ends with a period. If a demand shows strong feeling, it can end with an exclamation point. For this assignment, use references to support your claims. Don't drive so quickly in the construction zone! An interrogative sentence asks a question and always ends with a question mark. Given the recent critiques of her new strategic plan, do you think the CEO will reconsider the company's direction? An exclamatory sentence is a statement that shows surprise or strong feeling. An exclamation always ends with an exclamation point. I can't wait to travel through Europe this summer!
The sentence is a statement and ends with a period. It is a declarative sentence.
What is the source of the allusion in the sentence below? Diana was known among her coworkers for her spartan ways.
[ "the Bible", "Greek history" ]
1
closed choice
grade10
language science
figurative-language
Literary devices
Recall the source of an allusion
An allusion is a brief mention of something or someone well known, often from mythology, history, or literature. An allusion lets you reference ideas from an entire story in just a few words. "I'd better get home before I turn into a pumpkin!" Lila remarked. Here, Lila alludes to the fairy tale "Cinderella," in which Cinderella must leave the ball before the coach that brought her transforms into a pumpkin. The allusion shows that Lila must depart immediately.
The source of the allusion spartan is Greek history. Soldiers from the city of Sparta in ancient Greece were known for their self-restraint, self-discipline, and indifference to luxury. The allusion spartan means simple and austere.
Complete the sentence so that it uses personification. The heavy door () as Edna pushed it open.
[ "protested", "creaked" ]
0
closed choice
grade8
language science
writing-strategies
Creative techniques
Use personification
Personification is giving human characteristics to nonhuman things. It is a figure of speech that can be used to make writing more interesting or to emphasize a point. The trees danced in the wind. The word danced describes the trees as if they were people. Unlike people, however, trees can't actually dance. Instead, the personification suggests that the trees are moving.
Complete the sentence with the word protested. It describes the door as if it were a person who didn't want to obey.
Would you find the word material on a dictionary page with the following guide words? midst - mosquito
[ "yes", "no" ]
1
yes or no
grade4
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since material is not between the guide words midst - mosquito, it would not be found on that page.
Which closing is correct for a letter?
[ "Best Wishes,\nHelen", "Best wishes,\nHelen" ]
1
closed choice
grade3
language science
punctuation
Formatting
Greetings and closings of letters
A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory
The second closing is correct: Its first word is capitalized, and it ends with a comma.
Which logical fallacy is used in the text? Mayor Preston wants to create more bicycle lanes in Bloomington. However, many citizens of Bloomington live far from work. It would not be realistic to force us to give up our cars and bike everywhere.
[ "appeal to nature: the assumption that natural things are always good", "straw man: a misrepresentation of an opponent's position that makes it easier to argue against", "guilt by association: a negative association intended to discredit someone or something" ]
1
closed choice
grade12
language science
writing-strategies
Developing and supporting arguments
Classify logical fallacies
A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions. A logical fallacy may present irrelevant information: Fallacy | Description ad hominem | an attack against the person making the argument, rather than the argument itself appeal to nature | an argument that assumes the natural choice is always the best choice bandwagon fallacy | an argument that assumes the popular choice is always the best choice circular reasoning | an argument that supports a claim with the claim itself guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something A logical fallacy may misrepresent the issues at hand: Fallacy | Description false causation | the assumption that because two things happened together, one caused the other false dichotomy | an argument that presents only two choices when more options exist hasty generalization | a broad claim based on too few observations slippery slope fallacy | the false assumption that a small first step will necessarily lead to extreme consequences straw man | a misrepresentation of an opponent's position that makes it easier to argue against
The text argues that Mayor Preston wants people to give up their cars. However, this misrepresents Mayor Preston's argument. Mayor Preston only wants to create more bike lanes. This illustrates a type of logical fallacy known as a straw man.
Which type of sentence is this? Aisha is a competitive horseback rider, and she will be competing in the next World Equestrian Games, which are held every four years.
[ "complex", "compound-complex", "simple", "compound" ]
1
closed choice
grade9
language science
grammar
Phrases and clauses
Is the sentence simple, compound, complex, or compound-complex?
A clause is a group of words that contains both a subject and a predicate. An independent clause is a complete thought that can stand alone as a sentence. A dependent clause (or subordinate clause) is not a complete thought and cannot stand alone as a sentence. the oranges on our tree are ripe The clause can stand alone. It is independent. after we pick up Kevin from work The clause cannot stand alone. It is dependent. A simple sentence is made up of a single independent clause. Ben and I spent all day relaxing by the pool. Some simple sentences have introductory phrases, but the introductory phrase is part of the predicate. In the winter, Ben usually wears his heavy coat. Ben usually wears his heavy coat in the winter. A compound sentence is made up of two independent clauses joined by a coordinating conjunction such as and, but, or, or so. We saw the flash of lightning, and seconds later we heard a rumble of thunder. A complex sentence is made up of an independent clause and a dependent clause. The dependent clause in a complex sentence usually begins with a subordinating conjunction or relative pronoun. Subordinating conjunctions include after, although, as, because, before, if, since, unless, until, when, and while. Relative pronouns include that, which, who, whom, or whose. If she ever gets the chance, Terri would love to visit the Egyptian pyramids. During his trip to Italy, Tony visited the Trevi Fountain, which is in Rome. A compound-complex sentence is made up of two or more independent clauses and one or more dependent clauses. After Samantha left work, she stopped at the bank, and then she went to the gym. Sometimes a dependent clause in a complex or compound-complex sentence can interrupt an independent clause. Orcas that are kept in captivity often have bent dorsal fins.
The sentence is compound-complex. It is made up of two independent clauses and a dependent clause. The dependent clause begins with the relative pronoun which. Aisha is a competitive horseback rider, and she will be competing in the next World Equestrian Games, which are held every four years.
Select the one animal that has all of the arachnid traits listed above.
[ "White-spotted octopuses have tentacles, which are also called arms. White-spotted octopuses can use their tentacles to reach between corals and grab fish. These octopuses have a soft red body with white spots.", "Leaf-curling spiders spin webs with a leaf at the center. These spiders have an exoskeleton and eight legs, but no antennae." ]
1
Arachnids are a group of animals with similar traits. The following traits can be used to identify arachnids: They have eight legs. They have an exoskeleton. They have no antennae. Observe the animals and read the descriptions.
closed choice
grade5
natural science
biology
Classification
Use evidence to classify animals
Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live. How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group.
To decide if an animal is part of a group, look at the traits of the group. Arachnids have the following traits: They have eight legs. They have an exoskeleton. They have no antennae. Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits. A leaf-curling spider has the following traits: It has eight legs. It has an exoskeleton. It has no antennae. A leaf-curling spider has the traits of an arachnid. A leaf-curling spider is an arachnid. A white-spotted octopus has the following traits: It has a soft body. It has tentacles. A white-spotted octopus does not have all of the traits of an arachnid. A white-spotted octopus is a mollusk.
What kind of sentence is this? Please take some time to think about my offer before you respond.
[ "exclamatory", "interrogative", "imperative" ]
2
closed choice
grade6
language science
punctuation
Sentences, fragments, and run-ons
Is the sentence declarative, interrogative, imperative, or exclamatory?
There are four kinds of sentences. A declarative sentence is a statement, and it always ends with a period. The nurse told Mr. Abrams to roll up his sleeve so that she could check his blood pressure. An interrogative sentence is a question, and it always ends with a question mark. Do you have any plans for the upcoming weekend? An imperative sentence is a command. It makes a request or tells someone to do something, and it usually ends with a period. If the command shows strong feeling, it ends with an exclamation point. For this assignment, use references to support your claims. Don't drive so quickly in the construction zone! An exclamatory sentence is like a statement, but it shows surprise or strong feeling. An exclamatory sentence always ends with an exclamation point. I can't wait to travel through Europe this summer!
The sentence makes a request, so it is an imperative sentence. Here, it ends with a period.
Which text uses the word can in its traditional sense?
[ "Gina can type using a keyboard with a QWERTY layout, but she prefers the Dvorak layout. The two keyboards have different arrangements of letters and symbols.", "If Gina prefers a keyboard with the Dvorak layout, she can use mine. In my opinion, it's faster than typing on a keyboard with a QWERTY layout." ]
0
closed choice
grade12
language science
writing-strategies
Word usage and nuance
Explore words with new or contested usages
Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.
The second text uses can in its traditional sense: to have the ability to. Gina can type using a keyboard with a QWERTY layout, but she prefers the Dvorak layout. The two keyboards have different arrangements of letters and symbols. The first text uses can in its nontraditional sense: to have permission to. If Gina prefers a keyboard with the Dvorak layout, she can use mine. In my opinion, it's faster than typing on a keyboard with a QWERTY layout. Most style guides recommend to use the traditional sense of the word can because it is considered more standard.
Which is a compound sentence?
[ "Last year the state received more than thirty inches of snow.", "We have a spare tire, but it is flat, too." ]
1
closed choice
grade3
language science
grammar
Sentences, fragments, and run-ons
Is the sentence simple or compound?
A simple sentence is a sentence with only one subject and predicate. The pitcher threw the ball to first base. A compound sentence is two simple sentences joined by a comma and a conjunction such as and, but, or, or so. The pitcher threw the ball, and the batter hit it. Some simple sentences have a compound subject or a compound predicate, but they are not compound sentences. Anna and James will watch the fireworks tonight. This simple sentence has a compound subject, Anna and James. The singers bowed and walked off the stage. This simple sentence has a compound predicate, bowed and walked off the stage. Some simple sentences have introductory phrases, but they are not compound sentences. The introductory phrase is part of the predicate. In the winter, Farmer Ben wears his heavy coat. This is a simple sentence. There is one subject, Farmer Ben, and one predicate, wears his heavy coat in the winter.
The first sentence is the compound sentence. It is made up of two simple sentences joined by a comma and the conjunction but. We have a spare tire, but it is flat, too.
Which word would you find on a dictionary page with the following guide words? scenery - social
[ "stall", "smuggle" ]
1
closed choice
grade7
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since smuggle is between the guide words scenery - social, it would be found on that page.
Which greeting is correct for a letter?
[ "Dear Uncle Tom,", "Dear uncle tom," ]
0
closed choice
grade4
language science
punctuation
Formatting
Greetings and closings of letters
A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory
The second greeting is correct: Its first word is capitalized, and it ends with a comma. Uncle Tom is capitalized because it is a proper noun.
Would you find the word rumble on a dictionary page with the following guide words? remote - rob
[ "yes", "no" ]
1
yes or no
grade8
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since rumble is not between the guide words remote - rob, it would not be found on that page.
Which closing is correct for a letter?
[ "Your Student,\nCarla", "Your student,\nCarla" ]
1
closed choice
grade3
language science
punctuation
Formatting
Greetings and closings of letters
A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory
The first closing is correct: Its first word is capitalized, and it ends with a comma.
Which is smoother?
[ "concrete sidewalk", "linen handkerchief" ]
1
closed choice
grade2
natural science
physics
Materials
Compare properties of materials
Every object is made of one or more materials. A material is a type of matter. Wood, glass, metal, and plastic are common materials. A material has different properties. A material's properties tell you how it looks, feels, tastes, or smells.
Smooth is a property. A smooth material is not rough or bumpy. Look at each picture, one at a time. Imagine touching the material shown in each picture. Of the choices, the linen handkerchief is smoother. If you touch linen fabric, it will not feel rough.
Which is a complex sentence?
[ "The package includes some old letters from my grandma to my dad and a broken pocket watch.", "After Patty returned from the Galápagos Islands, she showed Scott and Norma pictures of all the exotic animals." ]
1
closed choice
grade5
language science
grammar
Sentences, fragments, and run-ons
Is the sentence simple, compound, or complex?
A clause is a group of words that contains both a subject and a predicate. An independent clause is a complete thought. It can stand alone as a sentence. A dependent clause is not a complete thought. It cannot stand alone as a sentence. the oranges on our tree are ripe The clause can stand alone. It is independent. after we pick up Kevin from work The clause cannot stand alone. It is dependent. A simple sentence is made up of a single independent clause. Ben and I spent all day relaxing by the pool. Some simple sentences have introductory phrases, but the introductory phrase is part of the predicate. In the winter, Ben usually wears his heavy coat. Ben usually wears his heavy coat in the winter. A compound sentence is made up of two independent clauses joined by a coordinating conjunction such as and, but, or, or so. We saw a flash of lightning, and seconds later we heard the rumble of thunder. A complex sentence is made up of an independent clause and a dependent clause. The dependent clause usually begins with a subordinating conjunction such as after, although, as, because, before, if, since, unless, until, when, or while. If she ever gets the chance, Terri would love to visit the Egyptian pyramids.
The first sentence is the complex sentence. It is made up of an independent clause and a dependent clause. The dependent clause begins with the subordinating conjunction after. After Patty returned from the Galápagos Islands, she showed Scott and Norma pictures of all the exotic animals.
Based on this information, what is this tomato plant's genotype for the fruit texture gene?
[ "FF", "smooth fruit" ]
0
In a group of tomato plants, some individuals have smooth fruit and others have fuzzy fruit. In this group, the gene for the fruit texture trait has two alleles. The allele F is for smooth fruit, and the allele f is for fuzzy fruit. A certain tomato plant from this group has smooth fruit. This plant has two alleles for smooth fruit.
closed choice
grade7
natural science
biology
Genes to traits
Genetics vocabulary: genotype and phenotype
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.
An organism's genotype for a gene is its combination of alleles for that gene. The tomato plant has two alleles for smooth fruit (F). So, the plant's genotype for the fruit texture gene is FF.
Last year, there were seven men's clothing stores on Main Street in Stafford. This year, there are only three. What probably happened to the overall supply of men's shirts in Stafford?
[ "The supply probably went down.", "The supply probably went up." ]
0
closed choice
grade7
social science
economics
Supply and demand
Understand overall supply and demand
Overall supply is the total amount of a good or service that producers make and sell. There are several things that can make overall supply go up or down. The table below shows how changes to these things might affect overall supply. | Resources | Number of producers or suppliers | Expected change in demand Supply goes up | when resources cost less or are easier to get | when there are more producers or suppliers | when demand is expected to go up Supply goes down | when resources cost more or are harder to get | when there are fewer producers or suppliers | when demand is expected to go down Producers are people or companies that make goods or provide services. Suppliers are people or companies that sell goods or services. New inventions or technologies can also help workers produce goods and services more quickly. As a result of these changes, the supply of a good or service will often go up.
When four men's clothing stores closed on Main Street, the number of suppliers went down. There were fewer stores selling men's shirts. So, the supply of men's shirts probably went down.
Judaism (JU-dee-izm) is a religion that has existed for thousands of years. What are people who practice Judaism called?
[ "Jains", "Christians", "Jews", "Hindus" ]
2
closed choice
grade6
social science
world-history
World religions
Origins of Judaism
Today, people who practice Judaism, or actively follow its teachings and traditions, are called Jews. But there are also many Jews who don't take part in religious practices. These people may still think of themselves as Jews because of their ancestry, or family history. Early in Jewish history, ancestors of the first Jews were known as Hebrews and then Israelites.
Does this passage describe the weather or the climate? Chad noticed that the sky was filled with cumulus clouds every day last week.
[ "weather", "climate" ]
0
Hint: Weather is what the atmosphere is like at a certain place and time. Climate is the pattern of weather in a certain place.
closed choice
grade3
natural science
earth-science
Weather and climate
What's the difference between weather and climate?
The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.
Read the text carefully. Chad noticed that the sky was filled with cumulus clouds every day last week. This passage tells you about the clouds Chad saw last week. It describes the atmosphere at a certain place and time. So, this passage describes the weather.
What does the idiom in this text suggest? "Speak of the devil!" Shelley declared when Kenji strolled into the room.
[ "Shelley had just been speaking about Kenji.", "Shelley thought Kenji was a troublemaker." ]
0
closed choice
grade8
language science
figurative-language
Literary devices
Interpret figures of speech
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. An idiom is an expression that cannot be understood literally. Its meaning must be learned. The assignment was a piece of cake.
The text uses an idiom, an expression that cannot be understood literally. The idiom speak of the devil suggests that Shelley had just been speaking about Kenji. People say this when the person they've just been speaking about coincidentally arrives, as if summoned.
Which tense does the sentence use? Molly will exercise with Owen in the morning.
[ "future tense", "past tense", "present tense" ]
0
closed choice
grade4
language science
verbs
Verb tense
Is the sentence in the past, present, or future tense?
Present tense verbs tell you about something that is happening now. Most present-tense verbs are regular. They have no ending, or they end in -s or -es. Two verbs are irregular in the present tense, to be and to have. You must remember their forms. Past tense verbs tell you about something that has already happened. Most past-tense verbs are regular. They end in -ed. Some verbs are irregular in the past tense. You must remember their past-tense forms. Future tense verbs tell you about something that is going to happen. All future-tense verbs use the word will. Present | Past | Future walk, walks | walked | will walk go, goes | went | will go
The sentence is in future tense. You can tell because it uses will before the main verb, exercise. The verb tells you about something that is going to happen.
Compare the motion of three cars. Which car was moving at the lowest speed?
[ "a car that moved 140miles west in 10hours", "a car that moved 640miles east in 10hours", "a car that moved 355miles east in 10hours" ]
0
closed choice
grade3
natural science
physics
Force and motion
Compare the speeds of moving objects
An object's speed tells you how fast the object is moving. Speed depends on both distance and time. Distance tells you how far the object has moved. One unit used to measure distance is the mile. Time tells you how long the object has spent moving. One unit used to measure time is the hour. Think about objects moving for the same amount of time. The object that is moving the slowest will go the shortest distance in that time. It is moving at the lowest speed.
Look at the distance each car moved and the time it took to move that distance. The direction each car moved does not affect its speed. Notice that each car moved for 10 hours. The car that moved 140 miles moved the shortest distance in that time. So, that car must have moved at the lowest speed.
What do these two changes have in common? water evaporating from a puddle dry ice sublimating and becoming a gas
[ "Both are caused by cooling.", "Both are only physical changes.", "Both are chemical changes." ]
1
closed choice
grade8
natural science
chemistry
Chemical reactions
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.
Step 1: Think about each change. Water evaporating from a puddle is a change of state. So, it is a physical change. The liquid changes into a gas, but a different type of matter is not formed. Dry ice is solid carbon dioxide. When dry ice gets warm, it changes state and becomes carbon dioxide gas. This change of state, from solid to gas, is called sublimation. Dry ice becoming a gas is a physical change. A change of state does not form a different type of matter. Step 2: Look at each answer choice. Both are only physical changes. Both changes are physical changes. No new matter is created. Both are chemical changes. Both changes are physical changes. They are not chemical changes. Both are caused by heating. Both changes are caused by heating. Both are caused by cooling. Neither change is caused by cooling.
Complete the sentence. A flower petal turning brown is a ().
[ "chemical change", "physical change" ]
0
closed choice
grade5
natural science
chemistry
Physical and chemical change
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form new molecules. The types of molecules in matter before and after a chemical change are always different. Burning a piece of paper is a chemical change. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then relink and form different molecules. For example, carbon dioxide molecules are created when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. For example, water vaporizing is a physical change. Liquid water and water vapor are made of the same type of matter: water.
A flower petal turning brown is a chemical change. As the petal turns brown, the colorful matter in the petal breaks down and changes into a different type of matter.
Select the plant.
[ "Wombats eat plants.", "Wolves eat animals.", "Dahlias can grow colorful flowers.", "Dung beetles walk and run." ]
2
closed choice
grade3
natural science
biology
Classification
Identify plants and animals
Plants and animals are living things. Living things are called organisms. Plants come in many shapes and sizes. Most plants grow in the ground. They might grow leaves, flowers, and fruit. Plants cannot move around on their own like animals can. Animals also come in many shapes and sizes. Most animals can move around. Animals might run, swim, jump, or fly. Animals eat plants or other organisms for food.
A wombat is an animal. It eats plants. Wombats have strong claws. They use their claws to dig tunnels called burrows. A dung beetle is an animal. It walks and runs. Dung beetles eat animal waste, which is called dung. They roll the dung into balls to store for later. A dahlia is a plant. It can grow colorful flowers. Dahlia plants grow in the wild in Central America. But people grow dahlias in gardens all over the world! A wolf is an animal. It eats other animals. Wolves often live in family groups. A wolf family group is called a pack.
Which greeting is correct for a letter?
[ "Dear Mrs. Erickson,", "Dear mrs. erickson," ]
0
closed choice
grade4
language science
punctuation
Formatting
Greetings and closings of letters
A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory
The second greeting is correct: Its first word is capitalized, and it ends with a comma. Mrs. Erickson is capitalized because it is a proper noun.
Which of the following contains a vague pronoun reference?
[ "Jill told her sister that she couldn't go to the film festival because of final exams.", "Jill said that she couldn't go to the film festival with her sister because of final exams." ]
0
closed choice
grade10
language science
writing-strategies
Pronouns
Identify vague pronoun references
When writing, make sure to avoid vague pronoun references. A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent. When Lisa and Kim finally landed, she breathed a sigh of relief. The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear. Vague pronoun references can be corrected in one of two ways: 1. Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief. 2. Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed. A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent. They say that this nail polish dries in less than five minutes. The pronoun they is used without its antecedent, so the meaning of the sentence is unclear. This problem can be fixed by replacing the pronoun with its missing antecedent. The advertisements say that this nail polish dries in less than five minutes.
The first answer choice contains a vague pronoun reference. The pronoun she could refer to Jill or her sister. Jill told her sister that she couldn't go to the film festival because of final exams. The second answer choice shows a possible correction for the vague pronoun reference. The text has been rewritten so that the meaning is clear. Jill said that she couldn't go to the film festival with her sister because of final exams.
Which text uses the word nauseous in its traditional sense?
[ "Brooke couldn't tolerate the nauseous odor emanating from the landfill, so she rolled up her car windows as she drove past.", "The odor emanating from the landfill made Brooke so nauseous that she had to roll up the car windows as she drove past." ]
0
closed choice
grade12
language science
writing-strategies
Word usage and nuance
Explore words with new or contested usages
Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.
The first text uses nauseous in its traditional sense: causing disgust or nausea. Brooke couldn't tolerate the nauseous odor emanating from the landfill, so she rolled up her car windows as she drove past. The second text uses nauseous in its nontraditional sense: feeling disgusted or nauseated. The odor emanating from the landfill made Brooke so nauseous that she had to roll up the car windows as she drove past. Most style guides recommend to use the traditional sense of the word nauseous because it is considered more standard.
How long is a leather belt?
[ "25 miles", "25 inches", "25 yards", "25 feet" ]
1
Select the best estimate.
closed choice
grade7
natural science
units-and-measurement
Units and measurement
Choose customary units of distance, mass, and volume
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. When you are using customary units, length may be written with units of inches, feet, yards, or miles. There are 12 inches in 1 foot, and 3 feet in 1 yard. There are 5,280 feet in 1 mile. A football is about 1 foot long. A football field is 100 yards long.
The best estimate for the length of a leather belt is 25 inches. 25 feet, 25 yards, and 25 miles are all too long.
What information supports the conclusion that Ava inherited this trait?
[ "Ava's father has brown eyes. He passed this trait down to Ava.", "Ava's hair is the same color as her brown eyes." ]
0
Read the description of a trait. Ava has brown eyes.
closed choice
grade3
natural science
biology
Heredity
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment.
Using only these supplies, which question can Malik investigate with an experiment?
[ "Do watercolor paintings dry faster when placed next to a fan?", "Do watercolor paintings dry faster when they are placed inside or outside?", "Does a large watercolor painting or a small watercolor painting dry faster?" ]
1
Malik is painting watercolor pictures with his friend. An hour after they have finished, Malik notices one painting is dry but the other is not. He wonders what factors affect how quickly watercolor paintings dry. So, he decides to design an experiment. He has the following supplies available: two freshly painted watercolor pictures of the same size his dining room table a picnic table in his backyard a heater
closed choice
grade8
natural science
science-and-engineering-practices
Designing experiments
Identify questions that can be investigated with a set of materials
Experiments can be designed to answer specific questions. When designing an experiment, you must identify the supplies that are necessary to answer your question. In order to do this, you need to figure out what will be tested and what will be measured during the experiment. Imagine that you are wondering if plants grow to different heights when planted in different types of soil. How might you decide what supplies are necessary to conduct this experiment? First, you need to identify the part of the experiment that will be tested, which is the independent variable. This is usually the part of the experiment that is different or changed. In this case, you would like to know how plants grow in different types of soil. So, you must have different types of soil available. Next, you need to identify the part of the experiment that will be measured or observed, which is the dependent variable. In this experiment, you would like to know if some plants grow taller than others. So, you must be able to compare the plants' heights. To do this, you can observe which plants are taller by looking at them, or you can measure their exact heights with a meterstick. So, if you have different types of soil and can observe or measure the heights of your plants, then you have the supplies you need to investigate your question with an experiment!
What does the verbal irony in this text suggest? "That fits you well," Ezra remarked after Anna's cap fell over her eyes for the tenth time.
[ "The cap was too big.", "The cap was a good fit." ]
0
closed choice
grade7
language science
figurative-language
Literary devices
Interpret figures of speech
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic. Olivia seems thrilled that her car keeps breaking down. Each breakdown is as enjoyable as a punch to the face.
The text uses verbal irony, which involves saying one thing but implying something very different. Fits you well ironically suggests that the cap was too big. The cap was falling over Anna's eyes, so it didn't fit her well at all.
Does this passage describe the weather or the climate? June, July, and August are usually humid in New Orleans, Louisiana.
[ "climate", "weather" ]
0
closed choice
grade5
natural science
earth-science
Weather and climate
What's the difference between weather and climate?
The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.
Read the text carefully. June, July, and August are usually humid in New Orleans, Louisiana. Humidity is the amount of water in the air. This passage tells you about the usual summer humidity in New Orleans. It does not describe what the weather is like on a particular day. So, this passage describes the climate.
Select the animal that has a backbone.
[ "pelican", "bumble bee" ]
0
Hint: Mammals, birds, fish, reptiles, and amphibians all have backbones.
closed choice
grade2
natural science
biology
Classification
Identify animals with and without backbones
Some animals have a backbone. The backbone is made of many bones in an animal's back. An animal's backbone helps connect the different parts of its body. In the drawings below, each animal's backbone is colored orange. Other animals do not have a backbone. In fact, these animals don't have any bones! Some animals without backbones have a hard outer cover. Other animals have a soft body.
A pelican is a bird. Like other birds, a pelican has a backbone. A bumble bee is an insect. Like other insects, a bumble bee does not have a backbone. It has a hard outer cover.
Suppose Amanda decides to go on the pirate ship. Which result would be a cost?
[ "Amanda will give up the chance to go on the Ferris wheel. She would have had more fun on that ride.", "Amanda will save some ride tickets. She needs fewer tickets to go on the pirate ship than on the Ferris wheel." ]
0
Amanda is deciding which ride to go on at the fair. She can go on either the Ferris wheel or the pirate ship. She wants to have as much fun as possible at the fair.
closed choice
grade5
social science
economics
Basic economic principles
Costs and benefits
Before you decide to do something, it is often helpful to list costs and benefits. Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need. Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Amanda wants or needs: Amanda will give up the chance to go on the Ferris wheel. She would have had more fun on that ride.
Select the living thing.
[ "pushpin", "robin" ]
1
closed choice
grade3
natural science
biology
Classification
Identify living and nonliving things
All living things need food and water. Water helps living things break down food and remove waste. Food gives living things energy. Living things use this energy to grow and change. All living things grow and change during their lives. All living things sense changes in the world around them. Living things might sense changes by seeing, smelling, hearing, or feeling. Living things can respond to the changes they sense.
A pushpin is not a living thing. Pushpins do not have all of the traits of living things. They do not grow or respond to the world around them. They do not need food or water. A robin is a living thing. Robins grow and respond to the world around them. They need food and water.
Which figure of speech is used in this text? When Mona first joined the track team, she was afraid of jumping, but she got over that hurdle.
[ "verbal irony", "pun" ]
1
closed choice
grade10
language science
figurative-language
Literary devices
Classify figures of speech: review
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Alliteration is the repetition of sounds at the beginning of nearby words. What a lucky little lady you are! An allusion is a brief reference to something or someone well known, often from history or literature. "I'd better get home before I turn into a pumpkin!" Lila remarked. An idiom is an expression that cannot be understood literally. Its meaning must be learned. The assignment was a piece of cake. A simile uses like or as to compare two things that are not actually alike. The cat's fur was as dark as the night. A metaphor compares two things that are not actually alike without using like or as. The snow formed a blanket over the town. Onomatopoeia involves using a word that expresses a sound. The scrambled eggs hit the floor with a splat. Personification is giving human characteristics to nonhuman things. The trees danced in the wind. A pun involves using a word or phrase in a humorous way that suggests more than one meaning. A great new broom is sweeping the nation. Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic. Olivia seems thrilled that her car keeps breaking down. Each breakdown is as enjoyable as a punch to the face.
The text uses a pun, a word or phrase that humorously suggests more than one meaning. Hurdle refers to an obstacle that one must overcome. It also refers to an object that a runner jumps over.
What is the source of the allusion in the sentence below? Warren described the situation he was facing with his boss as a catch-22.
[ "a song", "literature" ]
1
closed choice
grade9
language science
figurative-language
Literary devices
Recall the source of an allusion
An allusion is a brief mention of something or someone well known, often from mythology, history, or literature. An allusion lets you reference ideas from an entire story in just a few words. "I'd better get home before I turn into a pumpkin!" Lila remarked. Here, Lila alludes to the fairy tale "Cinderella," in which Cinderella must leave the ball before the coach that brought her transforms into a pumpkin. The allusion shows that Lila must depart immediately.
The source of the allusion catch-22 is literature. Joseph Heller coined the term "catch-22" in his 1961 novel of the same name. In the novel, if an army pilot wants to avoid dangerous missions, he must be deemed mentally unfit; however, his desire to stay safe proves his sanity, so he can never be excused from a mission. Heller called this sort of predicament or dilemma a catch-22. The allusion catch-22 means a no-win situation.
Complete the sentence. Saliva breaking down a piece of bread is a ().
[ "chemical change", "physical change" ]
0
closed choice
grade6
natural science
chemistry
Chemical reactions
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form new molecules. The types of molecules in matter before and after a chemical change are always different. Burning a piece of paper is a chemical change. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then relink and form different molecules. For example, carbon dioxide molecules are created when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. For example, water vaporizing is a physical change. Liquid water and water vapor are made of the same type of matter: water.
Saliva breaking down a piece of bread is a chemical change. Bread is made up mostly of a chemical called starch. Saliva breaks the bonds between atoms in the starch molecules. The atoms then link together to form smaller, simpler molecules of sugar. The sugar is a different type of matter than the starch.
What does the metaphor in this text suggest? Kiara felt a roller coaster of emotions when she heard the news.
[ "Kiara found the news scary.", "Kiara had varied feelings." ]
1
closed choice
grade12
language science
figurative-language
Literary devices
Interpret the figure of speech
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. A metaphor compares two things that are not actually alike without using like or as. The snow formed a blanket over the town.
The text uses a metaphor, comparing two things that are not actually alike without using like or as. The metaphor Kiara felt a roller coaster of emotions suggests that Kiara had varied feelings. A roller coaster has a dramatic mix of ups and downs, and so do Kiara's feelings.
Is the following trait inherited or acquired? Emmy knows how to type.
[ "inherited", "acquired" ]
1
Hint: Typing takes practice.
closed choice
grade4
natural science
biology
Traits and heredity
Identify inherited and acquired traits
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits.
People are not born knowing how to type. Instead, many people learn how to type. So, typing is an acquired trait.
Based on this information, what is this rose plant's genotype for the flower color gene?
[ "FF", "light yellow flowers" ]
0
In a group of rose plants, some individuals have light yellow flowers and others have dark yellow flowers. In this group, the gene for the flower color trait has two alleles. The allele F is for light yellow flowers, and the allele f is for dark yellow flowers. A certain rose plant from this group has light yellow flowers. This plant has two alleles for light yellow flowers.
closed choice
grade8
natural science
biology
Genes to traits
Genetics vocabulary: genotype and phenotype
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.
An organism's genotype for a gene is its combination of alleles for that gene. The rose plant has two alleles for light yellow flowers (F). So, the plant's genotype for the flower color gene is FF.
Is the following statement true or false? A plant cell has a cell wall.
[ "true", "false" ]
0
true-or false
grade4
natural science
biology
Cells
Cell part functions: true or false
A plant cell has a cell wall. This statement is true. Not every cell has a cell wall, but a plant cell has one. The cell wall gives a plant cell its fixed shape.
What is the mass of a vacuum cleaner?
[ "20 pounds", "20 tons", "20 ounces" ]
0
Select the best estimate.
closed choice
grade5
natural science
units-and-measurement
Units and measurement
Choose customary units of mass
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Mass is a measurement of how much matter something contains. There are many different units of mass. When you are using customary units, mass may be written with units of ounces, pounds, or tons. There are 16 ounces in 1 pound and 2,000 pounds in 1 ton. So, 1 ounce is less than 1 pound and much less than 1 ton. A slice of bread has a mass of about 1 ounce, while a can of beans has a mass of about 1 pound. A small car has a mass of about 1 ton.
The best estimate for the mass of a vacuum cleaner is 20 pounds. 20 ounces is too light and 20 tons is too heavy.
Is the following statement true or false? Plant cells do not have mitochondria.
[ "false", "true" ]
0
true-or false
grade4
natural science
biology
Cells
Cell part functions: true or false
Plant cells do not have mitochondria. This statement is false. Not all cells have mitochondria, but most plant and animal cells have them.
Which change best matches the sentence? A glacier carries small rocks and boulders as it moves down a mountain.
[ "drought", "meteorite crash", "erosion" ]
2
closed choice
grade3
natural science
earth-science
Earth events
Classify changes to Earth's surface II
Which figure of speech is used in this text? Amy's Bistro used to be a great place to go for a delicious and carefully prepared dinner, but nobody goes there anymore: it's too crowded.
[ "euphemism", "paradox" ]
1
closed choice
grade11
language science
figurative-language
Literary devices
Classify the figure of speech: euphemism, hyperbole, oxymoron, paradox
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic. The head of Human Resources would never refer to firing people, only to laying them off. Hyperbole is an obvious exaggeration that is not meant to be taken literally. I ate so much that I think I might explode! An oxymoron is a joining of two seemingly contradictory terms. Some reviewers are calling this book a new classic. A paradox is a statement that might at first appear to be contradictory, but that may in fact contain some truth. Always expect the unexpected.
The text uses a paradox, a statement that might at first appear to be contradictory, but that may in fact contain some truth. Nobody goes there anymore: it's too crowded at first appears to be contradictory, because if no one goes to the restaurant, then the restaurant should be empty, not crowded. However, it contains some truth: if a restaurant is frequently perceived to be too crowded, many people will no longer want to go there.
Which figure of speech is used in this text? "This box weighs a ton!" Martin panted. "Carly, would you mind helping me carry it up the stairs?"
[ "understatement", "hyperbole" ]
1
closed choice
grade11
language science
figurative-language
Literary devices
Classify the figure of speech: review
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Anaphora is the repetition of the same word or words at the beginning of several phrases or clauses. We are united. We are powerful. We are winners. Antithesis involves contrasting opposing ideas within a parallel grammatical structure. I want to help, not to hurt. Apostrophe is a direct address to an absent person or a nonhuman entity. Oh, little bird, what makes you sing so beautifully? Assonance is the repetition of a vowel sound in a series of nearby words. Try to light the fire. Chiasmus is an expression in which the second half parallels the first but reverses the order of words. Never let a fool kiss you or a kiss fool you. A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic. The head of Human Resources would never refer to firing people, only to laying them off. Hyperbole is an obvious exaggeration that is not meant to be taken literally. I ate so much that I think I might explode! An oxymoron is a joining of two seemingly contradictory terms. Some reviewers are calling this book a new classic. A paradox is a statement that might at first appear to be contradictory, but that may in fact contain some truth. Always expect the unexpected. Understatement involves deliberately representing something as less serious or important than it really is. As you know, it can get a little cold in the Antarctic.
The text uses hyperbole, an obvious exaggeration that is not meant to be taken literally. A ton is an exaggeration, since it would be impossible for one or two people to carry a box that weighed a ton, or 2000 pounds.
Complete the sentence. Burning a candle is a ().
[ "chemical change", "physical change" ]
0
closed choice
grade5
natural science
chemistry
Physical and chemical change
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form new molecules. The types of molecules in matter before and after a chemical change are always different. Burning a piece of paper is a chemical change. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then relink and form different molecules. For example, carbon dioxide molecules are created when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. For example, water vaporizing is a physical change. Liquid water and water vapor are made of the same type of matter: water.
Burning a candle is a chemical change. Both the wick and the melted wax burn. They react with oxygen in the air and turn into soot, carbon dioxide, and water.