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ScienceQA

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Which tense does the sentence use? Reba chops onions for the tomato sauce.

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 present tense. You can tell because it uses a present-tense verb, chops. The verb ends in -s and tells you about something that is true or happening now.

What do these two changes have in common? a slice of banana turning brown grilling a hamburger

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. A slice of banana turning brown is a chemical change. The part of the banana in contact with the air reacts with oxygen and turns into a different type of matter. Grilling a hamburger is a chemical change. Heat from the grill causes the matter in the meat to change. Cooked meat and raw meat are different types of matter. 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. Cooking a hamburger is caused by heating. But a slice of banana turning brown is not. Both are caused by cooling. Neither change is caused by cooling.

Select the organism in the same genus as the crystal jellyfish.

This organism is a crystal jellyfish. Its scientific name is Aequorea victoria.

closed choice

grade7

natural science

biology

Classification and scientific names

Use scientific names to classify organisms

Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.

A crystal jellyfish's scientific name is Aequorea victoria. The first word of its scientific name is Aequorea. This organism and the crystal jellyfish are in the same genus and the same species! Both organisms have the same scientific name, Aequorea victoria. Goura victoria and Aequorea victoria are not in the same genus. These organisms are not in the same genus, but part of their scientific names is the same. Goura victoria and Aequorea victoria have the same species name within their genus, victoria. But the first words of their scientific names are different. Goura victoria is in the genus Goura, and Aequorea victoria is in the genus Aequorea. Larus occidentalis is in the genus Larus. The first word of its scientific name is Larus. So, Larus occidentalis and Aequorea victoria are not in the same genus.

Which solution has a higher concentration of green particles?

The diagram below is a model of two solutions. Each green ball represents one particle of solute.

closed choice

grade7

natural science

chemistry

Solutions

Compare concentrations of solutions

A solution is made up of two or more substances that are completely mixed. In a solution, solute particles are mixed into a solvent. The solute cannot be separated from the solvent by a filter. For example, if you stir a spoonful of salt into a cup of water, the salt will mix into the water to make a saltwater solution. In this case, the salt is the solute. The water is the solvent. The concentration of a solute in a solution is a measure of the ratio of solute to solvent. Concentration can be described in terms of particles of solute per volume of solvent. concentration = particles of solute / volume of solvent

In Solution A and Solution B, the green particles represent the solute. To figure out which solution has a higher concentration of green particles, look at both the number of green particles and the volume of the solvent in each container. Use the concentration formula to find the number of green particles per milliliter. Solution A has more green particles per milliliter. So, Solution A has a higher concentration of green particles.

What is the volume of a bowl of soup?

Select the best estimate.

closed choice

grade5

natural science

units-and-measurement

Units and measurement

Choose customary 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 customary units, volume may be written in units of fluid ounces, cups, or gallons. As the diagram shows, there are 8 fluid ounces in 1 cup and 16 cups in 1 gallon. So, 1 fluid ounce is less than 1 cup and much less than 1 gallon. A glass of milk has a volume of about 8 fluid ounces, or 1 cup. A jug of milk has a volume of 1 gallon.

The best estimate for the volume of a bowl of soup is 11 fluid ounces. 11 cups and 11 gallons are both too much.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.

closed choice

grade3

natural science

physics

Magnets

Compare strengths of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the strength of a magnetic force between two magnets by changing the distance between them. The magnetic force is stronger when the magnets are closer together.

Distance affects the strength of the magnetic force. When magnets are closer together, the magnetic force between them is stronger. The magnets in Pair 1 are closer together than the magnets in Pair 2. So, the magnetic force is stronger in Pair 1 than in Pair 2.

Which property do these four objects have in common?

Select the best answer.

closed choice

grade5

natural science

physics

Materials

Compare properties of objects

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it. Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.

Look at each object. For each object, decide if it has that property. Sugar has a sweet taste. All four objects are sweet. A translucent object lets light through. But you cannot see clearly through a translucent object. The apple juice is translucent, but the chocolate bar and the peach are not. A fuzzy object is covered in soft hair. The chocolate bar and the jam are not fuzzy. The property that all four objects have in common is sweet.

Which figure of speech is used in this text? "This mattress is as soft as concrete," Tyler complained as he tested the bed in his hotel room.

closed choice

grade7

language science

figurative-language

Literary devices

Classify 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. 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 verbal irony, which involves saying one thing but implying something very different. As soft as concrete shows verbal irony because concrete is not soft.

Ken starts to pull the wagon across the yard. To move the wagon at the same speed each time, which friend does Ken need to pull with a larger force?

Ken gives two friends a ride in his wagon. One friend sits in the wagon at a time.

closed choice

grade2

natural science

physics

Force and motion

How do mass and force affect motion?

A force is a push or a pull. A force can make an object start moving or stop an object that is moving. A force can also make an object speed up, slow down, or change direction. Forces can be different sizes. Think about trying to move a heavy object and a light object. Imagine you want to move them at the same speed. You will need to use a larger force to move the heavy object.

Look for the friend who is heavier. A friend who weighs 32 pounds is heavier than a friend who weighs 25 pounds. So, to move the wagon at the same speed each time, Ken needs to use a larger force to start moving the wagon with a friend who weighs 32 pounds.

Which type of force from the girl opens the window?

A girl applies a force to a window. She uses the force to open the window.

closed choice

grade3

natural science

physics

Force and motion

Identify pushes and pulls

A force is a push or a pull that one object applies to a second object. The direction of a push is away from the object that is pushing. The direction of a pull is toward the object that is pulling.

The girl applies a force to the window panes. This force opens the window. The direction of this force is away from the girl. This force is a push.

Which statement describes the Tallgrass Prairie National Preserve ecosystem?

Figure: Tallgrass Prairie National Preserve. Tallgrass Prairie National Preserve is a prairie grassland ecosystem in eastern Kansas. The preserve is named for its grass, which can grow over five feet tall. This type of grass once covered large parts of North America, but it is now rare. Most of the tallgrass in North America was destroyed to create farmland.

closed choice

grade8

natural science

biology

Ecosystems

Describe ecosystems

An environment includes all of the biotic, or living, and abiotic, or nonliving, things in an area. An ecosystem is created by the relationships that form among the biotic and abiotic parts of an environment. There are many different types of terrestrial, or land-based, ecosystems. Here are some ways in which terrestrial ecosystems can differ from each other: the pattern of weather, or climate the type of soil the organisms that live there

A prairie grassland is a type of ecosystem. Prairie grasslands have the following features: hot summers and cool winters, a medium amount of rain, and soil that is rich in nutrients. So, the following statement describes the Tallgrass Prairie National Preserve ecosystem: hot summers and cool winters, a medium amount of rain, and soil that is rich in nutrients. It has a medium amount of rain. The following statements do not describe Tallgrass Prairie National Preserve: hot summers and cool winters, a medium amount of rain, and soil that is rich in nutrients. It has soil that is poor in nutrients. It has cold winters and cool summers.

Is a travel bag a good or a service?

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 travel bag is a good or a service, ask these questions: Is a travel bag something you can touch? Yes. Is a travel bag a job you might pay someone else to do? No. So, a travel bag is a good.

What can Akira and Brooke trade to each get what they want?

Trade happens when people agree to exchange goods and services. People give up something to get something else. Sometimes people barter, or directly exchange one good or service for another. Akira and Brooke open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Akira wanted broccoli in her lunch and Brooke was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.

closed choice

grade6

social science

economics

Basic economic principles

Trade and specialization

Akira wanted broccoli in her lunch and Brooke was hoping for tomatoes. Look at the labeled part of the images. Akira has tomatoes. Brooke has broccoli. They can trade tomatoes for broccoli to both be happier. Trading other things would not help either person get more items they want.

What does the idiom in this text suggest? "Speak of the devil!" Whitney declared when Charlie strolled into the room.

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. 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 Whitney had just been speaking about Charlie. People say this when the person they've just been speaking about coincidentally arrives, as if summoned.

Which figure of speech is used in this text? "There's nothing I love more than skipping lunch," Mr. Crawford told the flight attendant when he learned that no food would be available on his cross-country flight.

closed choice

grade8

language science

figurative-language

Literary devices

Classify 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. 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 verbal irony, which involves saying one thing but implying something very different. Nothing I love more shows verbal irony because Mr. Crawford is probably upset that there isn't anything to eat.

Identify the question that Lily's experiment can best answer.

The passage below describes an experiment. Read the passage and then follow the instructions below. Lily glued lids onto 16 cardboard shoe boxes of equal size. She painted eight of the boxes black and eight of the boxes white. Lily made a small hole in the side of each box and then stuck a thermometer partially into each hole so she could measure the temperatures inside the boxes. She placed the boxes in direct sunlight in her backyard. Two hours later, she measured the temperature inside each box. Lily compared the average temperature inside the black boxes to the average temperature inside the white boxes. Figure: a shoebox painted black.

closed choice

grade6

natural science

science-and-engineering-practices

Designing experiments

Identify the experimental question

Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?

Last year, 50,000 people lived in the city of Belmont. But since then, 8,000 people have moved away. What probably happened to the overall supply of houses for sale in Belmont?

closed choice

grade3

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.

The population of Belmont fell by 8,000 people. Many of the people who have left are probably trying to sell their houses. Since more people are trying to sell their houses, the number of suppliers of houses for sale in Belmont has gone up. So, the supply of houses for sale probably went up, too.

What is this tarantula's scientific name?

This species of tarantula was discovered near Folsom Prison in California. It was named after the musician Johnny Cash, who sang about the prison and was often called "The Man in Black."

closed choice

grade4

natural science

biology

Scientific names

Origins of scientific names

When a scientist identifies a new organism, he or she chooses its scientific name. Sometimes, an organism is named after the place where it was first found. Other times, an organism is named after the scientist who first identified it. Or, the scientific name might describe the organism's physical traits. Many of the words that make up scientific names are based on words from old languages, like Latin and classical Greek. Sometimes, English words are changed to make them sound more like Latin or Greek. The new words are then used in an organism's scientific name.

This organism's scientific name refers to Johnny Cash. The word johnnycashi refers to Johnny Cash. So, this tarantula's scientific name is Aphonopelma johnnycashi.

Is the following trait inherited or acquired? Elijah plays hockey.

Hint: Playing hockey 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 play hockey. Instead, some people learn how to play hockey. Playing the sport takes practice. So, playing hockey is an acquired trait.

What is the capital of Washington?

closed choice

grade5

social science

geography

State capitals

Identify the 50 state capitals

Olympia is the capital of Washington.

Complete the sentence. In this chemical reaction, carbon dioxide is a ().

This passage describes a chemical reaction. Read the passage. Then, follow the instructions below. Plants make glucose, a sugar they can use for food, through a process called photosynthesis. During photosynthesis, plants use energy from sunlight to make glucose from water and carbon dioxide. In the process of making glucose, plants also create most of the oxygen in the air we breathe.

closed choice

grade7

natural science

chemistry

Chemical reactions

Identify reactants and products

A chemical change occurs when new substances are formed from existing substances. This process is called a chemical reaction. In a chemical reaction, one or more substances change into one or more different substances. During the reaction, the atoms of the original substances are rearranged to form other substances. The original substances in a chemical reaction are called reactants. These substances react, or go through a chemical change. The substances that are formed in a chemical reaction are called products. These substances are produced by the chemical reaction. So, in a chemical reaction, reactants go through a chemical change to form products.

Read the underlined text carefully. Look for information about what happens to carbon dioxide in this chemical reaction. Plants make glucose, a sugar they can use for food, through a process called photosynthesis. During photosynthesis, plants use energy from sunlight to make glucose from water and carbon dioxide. In the process of making glucose, plants also create most of the oxygen in the air we breathe. The underlined text tells you that when water and carbon dioxide combine, glucose and oxygen are formed. When water and carbon dioxide react, or go through a chemical change, their atoms are rearranged to form glucose and oxygen. Because carbon dioxide reacts in this chemical reaction, carbon dioxide is a reactant.

Which is a simple sentence?

closed choice

grade6

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 simple sentence. It is a single independent clause. Mr. Duran's afternoon lecture was about art and culture in Germany before World War II.

Which bird's beak is also adapted to get nectar out of long flowers?

Green violetears live in the forests of Central and South America. The shape of the 's beak is adapted to get nectar out of long flowers. Figure: green violetear.

closed choice

grade5

natural science

biology

Adaptations

Animal adaptations: beaks, mouths, and necks

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The shape of a bird's beak is one example of an adaptation. Birds' beaks can be adapted in different ways. For example, a sharp hooked beak might help a bird tear through meat easily. A short, thick beak might help a bird break through a seed's hard shell. Birds that eat similar food often have similar beaks.

Look at the picture of the green violetear. The green violetear has a long, thin beak. Its beak is adapted to get nectar out of long flowers. The green violetear's long, thin beak can reach deep into the flowers. Now look at each bird. Figure out which bird has a similar adaptation. The violet sabrewing has a long, thin beak. Its beak is adapted to get nectar out of long flowers. The ground hornbill has a large, long beak. Its beak is not adapted to get nectar out of long flowers. The ground hornbill uses its beak to catch, frogs, insects, and small mammals.

Which of these states is farthest north?

closed choice

grade4

social science

geography

Maps

Read a map: cardinal directions

Maps have four cardinal directions, or main directions. Those directions are north, south, east, and west. A compass rose is a set of arrows that point to the cardinal directions. A compass rose usually shows only the first letter of each cardinal direction. The north arrow points to the North Pole. On most maps, north is at the top of the map.

To find the answer, look at the compass rose. Look at which way the north arrow is pointing. Nebraska is farthest north.

What is the expected ratio of offspring with brown eyes to offspring with red eyes? Choose the most likely ratio.

In a group of guinea pigs, some individuals have brown eyes and others have red eyes. In this group, the gene for the eye color trait has two alleles. The allele for brown eyes (E) is dominant over the allele for red eyes (e). This Punnett square shows a cross between two guinea pigs.

closed choice

grade8

natural science

biology

Genes to traits

Use Punnett squares to calculate ratios of offspring types

Offspring phenotypes: dominant or recessive? How do you determine an organism's phenotype for a trait? Look at the combination of alleles in the organism's genotype for the gene that affects that trait. Some alleles have types called dominant and recessive. These two types can cause different versions of the trait to appear as the organism's phenotype. If an organism's genotype has at least one dominant allele for a gene, the organism's phenotype will be the dominant allele's version of the gene's trait. If an organism's genotype has only recessive alleles for a gene, the organism's phenotype will be the recessive allele's version of the gene's trait. A Punnett square shows what types of offspring a cross can produce. The expected ratio of offspring types compares how often the cross produces each type of offspring, on average. To write this ratio, count the number of boxes in the Punnett square representing each type. For example, consider the Punnett square below. | F | f F | FF | Ff f | Ff | ff There is 1 box with the genotype FF and 2 boxes with the genotype Ff. So, the expected ratio of offspring with the genotype FF to those with Ff is 1:2.

To determine how many boxes in the Punnett square represent offspring with brown eyes or red eyes, consider whether each phenotype is the dominant or recessive allele's version of the eye color trait. The question tells you that the E allele, which is for brown eyes, is dominant over the e allele, which is for red eyes. Brown eyes is the dominant allele's version of the eye color trait. A guinea pig with the dominant version of the eye color trait must have at least one dominant allele for the eye color gene. So, offspring with brown eyes must have the genotype EE or Ee. All 4 boxes in the Punnett square have the genotype EE or Ee. Red eyes is the recessive allele's version of the eye color trait. A guinea pig with the recessive version of the eye color trait must have only recessive alleles for the eye color gene. So, offspring with red eyes must have the genotype ee. There are 0 boxes in the Punnett square with the genotype ee. So, the expected ratio of offspring with brown eyes to offspring with red eyes is 4:0. This means that, based on the Punnett square, this cross will always produce offspring with brown eyes. This cross is expected to never produce offspring with red eyes.

Is the following trait inherited or acquired? Becky can fly an airplane.

Hint: Pilots have to learn how to fly an airplane.

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 fly an airplane. Instead, some people learn how to fly airplanes. So, flying an airplane is an acquired trait.

Which is a simple sentence?

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 simple sentence. It is a single independent clause. The audition for the part of Dracula will begin in just a few minutes.

How long is a sandbox?

Select the better estimate.

closed choice

grade3

natural science

units-and-measurement

Units and measurement

Choose metric units of distance

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Imagine being told that a pencil is 16 long. You might be thinking, 16 what? Is the pencil 16 centimeters long? 16 meters? 16 kilometers? The number 16 on its own does not give you much information about the length of the pencil. That is because the units are missing. Now look at the drawing of the pencil and the ruler. The ruler shows that the units are centimeters. So, the length of the pencil is 16 centimeters. There are 100 centimeters in 1 meter. So, 1 centimeter is much shorter than 1 meter. There are 1,000 meters in 1 kilometer. So, 1 meter is much shorter than 1 kilometer.

The better estimate for the length of a sandbox is 2 meters. 2 centimeters is too short.

What is the capital of Washington?

closed choice

grade3

social science

geography

State capitals

Identify the 50 state capitals

Olympia is the capital of Washington.

Would you find the word scoop on a dictionary page with the following guide words? seam - sheriff

yes or no

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 scoop is not between the guide words seam - sheriff, it would not be found on that page.

Which of these states is farthest east?

closed choice

grade2

social science

geography

Geography

Read a map: cardinal directions

Maps have four cardinal directions, or main directions. Those directions are north, south, east, and west. A compass rose is a set of arrows that point to the cardinal directions. A compass rose usually shows only the first letter of each cardinal direction. The north arrow points to the North Pole. On most maps, north is at the top of the map.

To find the answer, look at the compass rose. Look at which way the east arrow is pointing. New York is farthest east.

What is the capital of Vermont?

closed choice

grade5

social science

geography

State capitals

Identify state capitals of the Northeast

Montpelier is the capital of Vermont.

What information supports the conclusion that Ryan acquired this trait?

Read the description of a trait. Ryan knows how to build a fire.

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 correctly shows the title of a book?

closed choice

grade3

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, or article should be in quotation marks. "You Are My Sunshine"

A book should be in italics. The correct title is **Harold and the Purple Crayon**.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different sizes.

closed choice

grade8

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by using magnets of different sizes. The magnitude of the magnetic force is smaller when the magnets are smaller.

Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The smaller the magnets, the smaller the magnitude of the magnetic force between them. Magnet A is the same size in both pairs. But Magnet B is smaller in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is smaller in Pair 1 than in Pair 2.

Which of the following fossils is older? Select the more likely answer.

This diagram shows fossils in an undisturbed sedimentary rock sequence.

closed choice

grade8

natural science

earth-science

Fossils

Compare ages of fossils in a rock sequence

A fossil is the preserved evidence of an ancient organism. Some fossils are formed from body parts such as bones or shells. Other fossils, such as footprints or burrows, are formed from traces of an organism's activities. Fossils are typically found in sedimentary rocks. Sedimentary rocks usually form in layers. Over time, new layers are added on top of old layers in a series called a rock sequence. The layers in an undisturbed rock sequence are in the same order as when they formed. So, the deeper layers are older than the shallower layers. The relative ages of fossils can be determined from their positions in an undisturbed rock sequence. Older fossils are usually in deeper layers, and younger fossils are usually in shallower layers.

Look again at the fossils in the rock sequence diagram. Compare the positions of these fossils to determine which one is older: The dinosaur footprint fossil is in a deeper layer in the rock sequence than the fern fossil. So, the dinosaur footprint fossil is most likely older than the fern fossil.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade7

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

The particles in both samples have the same average speed, but each particle in sample A has more mass than each particle in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B. Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.

Which country is highlighted?

closed choice

grade6

social science

geography

The Americas: geography

Identify and select countries of the Caribbean

This country is Jamaica.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different sizes and shapes.

closed choice

grade7

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by using magnets of different sizes. The magnitude of the magnetic force is greater when the magnets are larger.

Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The larger the magnets, the greater the magnitude of the magnetic force between them. Magnet A is the same size in both pairs. But Magnet B is larger in Pair 2 than in Pair 1. So, the magnitude of the magnetic force is greater in Pair 2 than in Pair 1.

Which word would you find on a dictionary page with the following guide words? patient - private

closed choice

grade3

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 pit is between the guide words patient - private, it would be found on that page.

Which better describes the Shenandoah National Park ecosystem?

Figure: Shenandoah National Park. Shenandoah National Park is a temperate deciduous forest ecosystem in northern Virginia.

closed choice

grade3

natural science

biology

Ecosystems

Describe ecosystems

An ecosystem is formed when living and nonliving things interact in an environment. There are many types of ecosystems. Here are some ways in which ecosystems can differ from each other: the pattern of weather, or climate the type of soil or water the organisms that live there

A temperate deciduous forest is a type of ecosystem. Temperate deciduous forests have the following features: warm, wet summers and cold, wet winters, soil that is rich in nutrients, and only a few types of trees. So, Shenandoah National Park has warm, wet summers. It also has only a few types of trees.

Which correctly shows the title of a book?

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 book should be in italics. The correct title is **Bugs in My Hair**.

What is the mass of an elephant?

Select the better estimate.

closed choice

grade4

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 4,295 kilograms. 4,295 grams is too light.

Which is smoother?

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 silk necktie is smoother. If you touch silk fabric, it will not feel rough.

Which of the following could Emilia's test show?

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below. People with diabetes sometimes take a medicine made from insulin. Insulin can be made by a special type of bacteria. Emilia was a bioengineer who wanted to increase the amount of insulin that the bacteria produced by 20%. She read that giving the bacteria more nutrients could affect the amount of insulin they produced. So, Emilia gave extra nutrients to some of the bacteria. Then, she measured how much insulin those bacteria produced compared to bacteria that did not get extra nutrients. Figure: studying bacteria in a laboratory.

closed choice

grade7

natural science

science-and-engineering-practices

Engineering practices

Evaluate tests of engineering-design solutions

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. How can you determine what a test can show? You need to figure out what was tested and what was measured. Imagine an engineer needs to design a bridge for a windy location. She wants to make sure the bridge will not move too much in high wind. So, she builds a smaller prototype, or model, of a bridge. Then, she exposes the prototype to high winds and measures how much the bridge moves. First, identify what was tested. A test can examine one design, or it may compare multiple prototypes to each other. In the test described above, the engineer tested a prototype of a bridge in high wind. Then, identify what the test measured. One of the criteria for the bridge was that it not move too much in high winds. The test measured how much the prototype bridge moved. Tests can show how well one or more designs meet the criteria. The test described above can show whether the bridge would move too much in high winds.

What did the scientists discover?

Read the passage about a new discovery. A few scientists were looking for sharks when they saw something surprising. They found a sea turtle that glowed! The turtle's shell was bright red and green. This was a new discovery. Scientists had never seen a sea turtle with a glowing shell before. Scientists want to know why these turtles have a shell that glows. Sadly, there are not many of these turtles left in the world. So, it is hard to learn about them.

closed choice

grade2

language science

reading-comprehension

Independent reading comprehension

Read and understand informational passages

Look at the passage. It tells you what the scientists discovered. A few scientists were looking for sharks when they saw something surprising. They found a sea turtle that glowed! The turtle's shell was bright red and green. This was a new discovery. Scientists had never seen a sea turtle with a glowing shell before.

Which tense does the sentence use? Scientists will measure the rainfall in Lancaster.

closed choice

grade5

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, measure. The verb tells you about something that is going to happen.

Which continent is highlighted?

closed choice

grade5

social science

geography

Oceans and continents

Identify oceans and continents

A continent is one of the major land masses on the earth. Most people say there are seven continents.

This continent is North America.

Which ocean is highlighted?

closed choice

grade7

social science

geography

Physical Geography

Oceans and continents

Oceans are huge bodies of salt water. The world has five oceans. All of the oceans are connected, making one world ocean.

This is the Arctic Ocean.

Is a ring a solid or a liquid?

closed choice

grade2

natural science

physics

States of matter

Classify matter as solid or liquid

Solid and liquid are states of matter. Matter is anything that takes up space. Matter can come in different states, or forms. When matter is a solid, it has a shape of its own. Some solids can be bent or broken easily. Others are hard to bend or break. A glass cup is a solid. A sock is also a solid. When matter is a liquid, it takes the shape of its container. Think about pouring a liquid from a cup into a bottle. The shape of the liquid is different in the cup than in the bottle. But the liquid still takes up the same amount of space. Juice is a liquid. Honey is also a liquid.

A ring is a solid. A solid has a size and shape of its own. A ring keeps its shape, even when you take it off your finger.

Which material is this screw driver made of?

closed choice

grade2

natural science

physics

Materials

Identify multiple materials in objects

A material is a type of matter. Wood, glass, metal, and plastic are common materials. Some objects are made of just one material. Most nails are made of metal. Other objects are made of more than one material. This hammer is made of metal and wood.

Look at the picture of the screw driver. This screw driver is made of two different materials. The handle is made of plastic. The rest of the screw driver is made of metal. Metal is a good material for tools. Metal is hard and can be made into many shapes.

Use the evidence in the text to select the photosynthetic organism.

closed choice

grade7

natural science

biology

Photosynthesis

Identify the photosynthetic organism

Organisms that carry out photosynthesis are called photosynthetic organisms. During photosynthesis, these organisms use light energy, carbon dioxide, and water to produce sugars and oxygen. Photosynthetic organisms also often have the following characteristics: They are producers, which are organisms that make their own food inside their cells. Because producers make their own food, they typically do not eat other organisms. Their cells contain chloroplasts, which are cell structures where photosynthesis occurs. Their chloroplasts often contain a green substance called chlorophyll. Chlorophyll captures light energy from the Sun to power photosynthesis. They use the sugars they produce during photosynthesis as food. This food provides energy that helps the organisms live, grow, and reproduce.

This organism is photosynthetic: The text tells you that Sphagnum mosses get energy from the sugars they make using carbon dioxide and water. This is evidence that the Sphagnum moss is a photosynthetic organism. This organism is not photosynthetic: The text does not provide evidence that the mossy frog is photosynthetic.

Which part of the collard plant do we usually eat?

People use collard plants for food. Photosynthesis makes food for the plant. We usually eat the part of the plant that does most of the photosynthesis.

closed choice

grade4

natural science

biology

Plants

Classify fruits and vegetables as plant parts

The fruits and vegetables we eat are parts of plants! Plants are made up of different structures. The different structures carry out important functions. The roots take in water and nutrients from the soil. They also hold the plant in place in the soil. The stem supports the plant. It carries food, water, and nutrients through the plant. The leaves are where most of the plant's photosynthesis happens. Photosynthesis is the process plants use to turn water, sunlight, and carbon dioxide into food. After they are pollinated, the flowers make seeds and fruit. The fruit contain the seeds. Each fruit grows from a pollinated flower. The seeds can grow into a new plant. Germination is when a seed begins to grow.

The part of the collard plant we usually eat is the leaves. They do most of the photosynthesis to make food for the plant.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different shapes.

closed choice

grade6

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by changing the distance between them. The magnitude of the magnetic force is greater when there is a smaller distance between the magnets.

The magnets in Pair 1 attract. The magnets in Pair 2 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force. Distance affects the magnitude of the magnetic force. When there is a smaller distance between magnets, the magnitude of the magnetic force between them is greater. There is a smaller distance between the magnets in Pair 2 than in Pair 1. So, the magnitude of the magnetic force is greater in Pair 2 than in Pair 1.

Which country is highlighted?

closed choice

grade7

social science

geography

Oceania: geography

Identify and select countries of Oceania

This country is Palau.

What is the capital of Kentucky?

closed choice

grade4

social science

geography

State capitals

Identify state capitals of the Southeast

Frankfort is the capital of Kentucky.

Which property matches this object?

Select the better answer.

closed choice

grade3

natural science

physics

Materials

Identify properties of an object

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.

Look at the object. Think about each property. A colorful object has one or more bright colors. The kite is colorful. A sticky object can attach or stick to other things. The kite is not sticky.

Which country is highlighted?

closed choice

grade6

social science

geography

The Americas: geography

Identify and select countries of the Caribbean

This country is Cuba. Does Cuba have any territorial disputes? Cuba claims to own Guantanamo Bay Naval Base, which is a disputed territory. In other words, multiple countries or groups claim that the area rightfully belongs to them. The United States controls the area and uses it as a military base and prison. A treaty in 1903 gave the U.S. the right to rent the land from Cuba. But today, Cuba says that it had no choice but to accept the treaty. It wants the United States to leave the area and does not accept the rent money sent by the United States each year.

What is the probability that a Channel catfish produced by this cross will have a white body?

In a group of Channel catfish, some individuals have a brown body and others have a white body. In this group, the gene for the body color trait has two alleles. The allele for a brown body (B) is dominant over the allele for a white body (b). This Punnett square shows a cross between two Channel catfish.

closed choice

grade8

natural science

biology

Genes to traits

Use Punnett squares to calculate probabilities of offspring types

Offspring phenotypes: dominant or recessive? How do you determine an organism's phenotype for a trait? Look at the combination of alleles in the organism's genotype for the gene that affects that trait. Some alleles have types called dominant and recessive. These two types can cause different versions of the trait to appear as the organism's phenotype. If an organism's genotype has at least one dominant allele for a gene, the organism's phenotype will be the dominant allele's version of the gene's trait. If an organism's genotype has only recessive alleles for a gene, the organism's phenotype will be the recessive allele's version of the gene's trait. In a Punnett square, each box represents a different outcome, or result. Each of the four outcomes is equally likely to happen. Each box represents one way the parents' alleles can combine to form an offspring's genotype. Because there are four boxes in the Punnett square, there are four possible outcomes. An event is a set of one or more outcomes. The probability of an event is a measure of how likely the event is to happen. This probability is a number between 0 and 1, and it can be written as a fraction: probability of an event = number of ways the event can happen / number of equally likely outcomes You can use a Punnett square to calculate the probability that a cross will produce certain offspring. For example, the Punnett square below has two boxes with the genotype Ff. It has one box with the genotype FF and one box with the genotype ff. This means there are two ways the parents' alleles can combine to form Ff. There is one way they can combine to form FF and one way they can combine to form ff. | F | f F | FF | Ff f | Ff | ff Consider an event in which this cross produces an offspring with the genotype ff. The probability of this event is given by the following fraction: number of ways the event can happen / number of equally likely outcomes = number of boxes with the genotype ff / total number of boxes = 1 / 4.

How long is a pen?

Select the better estimate.

closed choice

grade3

natural science

units-and-measurement

Units and measurement

Choose metric units of distance

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Imagine being told that a pencil is 16 long. You might be thinking, 16 what? Is the pencil 16 centimeters long? 16 meters? 16 kilometers? The number 16 on its own does not give you much information about the length of the pencil. That is because the units are missing. Now look at the drawing of the pencil and the ruler. The ruler shows that the units are centimeters. So, the length of the pencil is 16 centimeters. There are 100 centimeters in 1 meter. So, 1 centimeter is much shorter than 1 meter. There are 1,000 meters in 1 kilometer. So, 1 meter is much shorter than 1 kilometer.

The better estimate for the length of a pen is 20 centimeters. 20 kilometers is too long.

What is the capital of Pennsylvania?

closed choice

grade3

social science

geography

State capitals

Identify state capitals of the Northeast

Harrisburg is the capital of Pennsylvania.

What kind of sentence is this? I write for the school newspaper.

closed choice

grade4

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. It tells about something. A declarative sentence always ends with a period. I have an older brother and a younger sister. An interrogative sentence is a question. It asks something. An interrogative sentence always ends with a question mark. How tall are you? An imperative sentence is a command. It makes a request or tells someone to do something. An imperative sentence usually ends with a period. If the command shows strong feeling, it ends with an exclamation point. Read the first chapter by next week. Look out for that car! An exclamatory sentence is like a statement, but it shows surprise or strong feeling. An exclamatory sentence always ends with an exclamation point. Some whales are over ninety feet long! I can't wait until tomorrow!

The sentence tells about something, and it ends with a period. It is a declarative sentence.

Which property matches this object?

Select the better answer.

closed choice

grade2

natural science

physics

Materials

Identify properties of an object

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.

Look at the object. Think about each property. A shiny object reflects a lot of light. The silver ring is shiny. Yellow is a color. This color is yellow. The silver ring is not yellow.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different sizes.

closed choice

grade6

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by using magnets of different sizes. The magnitude of the magnetic force is smaller when the magnets are smaller.

Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The smaller the magnets, the smaller the magnitude of the magnetic force between them. Magnet A is the same size in both pairs. But Magnet B is smaller in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is smaller in Pair 1 than in Pair 2.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade8

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

The particles in both samples have the same average speed, but each particle in sample A has more mass than each particle in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B. Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.

In this food chain, the macroalgae is a producer. Why?

This diagram shows a food chain from the River Frome, a freshwater ecosystem in England.

closed choice

grade4

natural science

biology

Ecosystems

Identify roles in food chains

Every organism needs food to stay alive. Organisms get their food in different ways. A food chain shows how organisms in an ecosystem get their food. Producers make their own food. Many producers use carbon dioxide, water, and sunlight to make sugar. This sugar is food for the producer. Consumers eat other organisms. Consumers cannot make their own food.

In this food chain, the macroalgae is a producer because it makes its own food. The macroalgae uses carbon dioxide, water, and sunlight to make its own food.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.

closed choice

grade7

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by changing the distance between them. The magnitude of the magnetic force is smaller when there is a greater distance between the magnets.

Distance affects the magnitude of the magnetic force. When there is a greater distance between magnets, the magnitude of the magnetic force between them is smaller. There is a greater distance between the magnets in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is smaller in Pair 1 than in Pair 2.

What is the capital of Massachusetts?

closed choice

grade4

social science

geography

State capitals

Identify state capitals of the Northeast

Boston is the capital of Massachusetts.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.

closed choice

grade6

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other.

The magnets in Pair 2 attract. The magnets in Pair 1 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force. Both magnet sizes and distance affect the magnitude of the magnetic force. The sizes of the magnets in Pair 1 are the same as in Pair 2. The distance between the magnets is also the same. So, the magnitude of the magnetic force is the same in both pairs.

What is the volume of a paper drinking cup?

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 paper drinking cup is 185 milliliters. 185 liters is too much.

What information supports the conclusion that Harry inherited this trait?

Read the description of a trait. Harry has wavy hair.

closed choice

grade7

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.

Select the organism in the same genus as the Victoria crowned pigeon.

This organism is a Victoria crowned pigeon. Its scientific name is Goura victoria.

closed choice

grade5

natural science

biology

Scientific names

Use scientific names to classify organisms

Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.

A Victoria crowned pigeon's scientific name is Goura victoria. The first word of its scientific name is Goura. Goura scheepmakeri is in the genus Goura. The first word of its scientific name is Goura. So, Goura scheepmakeri and Goura victoria are in the same genus. Aequorea victoria and Goura victoria are not in the same genus. These organisms are not in the same genus, but part of their scientific names is the same. Aequorea victoria and Goura victoria have the same species name within their genus, victoria. But the first words of their scientific names are different. Aequorea victoria is in the genus Aequorea, and Goura victoria is in the genus Goura. Falco sparverius is in the genus Falco. The first word of its scientific name is Falco. So, Falco sparverius and Goura victoria are not in the same genus.

Which drop of dish soap has a lower temperature?

Two drops of dish soap are identical except for their thermal energies.

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 slow down, the temperature goes down. The matter now has both less thermal energy and a lower 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 drops of dish soap are made of the same material and have the same mass. So, the drop of dish soap with less thermal energy has a lower temperature.

Which material is this belt made of?

closed choice

grade2

natural science

physics

Materials

Identify multiple materials in objects

A material is a type of matter. Wood, glass, metal, and plastic are common materials. Some objects are made of just one material. Most nails are made of metal. Other objects are made of more than one material. This hammer is made of metal and wood.

Look at the picture of the belt. The belt is made of two materials. The buckle is made of metal. The rest of the belt is made of leather.

Which word would you find on a dictionary page with the following guide words? scribble - spade

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 sleepy is between the guide words scribble - spade, it would be found on that page.

Which is a run-on sentence?

closed choice

grade3

language science

writing-strategies

Sentences, fragments, and run-ons

Is it a complete sentence, a fragment, or a run-on?

A sentence is a group of words that forms a complete thought. It has both a subject and a verb. My friends walk along the path. A sentence fragment is a group of words that does not express a complete thought. It is usually missing a subject or a verb. Knows the answer. This is a sentence fragment. It is missing a subject. Who knows the answer? She knows the answer. The bright red car. This is a sentence fragment. It is missing a verb. What did the bright red car do? The bright red car stopped. A run-on sentence is made up of two sentences that are joined without end punctuation or with just a comma. I knocked on the door it opened. It started raining, we ran inside. To fix a run-on sentence, separate it into two sentences. Add end punctuation after the first sentence, and capitalize the second sentence. I knocked on the door. It opened. It started raining. We ran inside. You can also fix a run-on sentence by rewriting it as a compound sentence. A compound sentence is two sentences joined by a comma and a conjunction such as and, but, or, or so. I knocked on the door, and it opened. It started raining, so we ran inside.

The event was exciting it had music, a show and food is a run-on sentence. It has two sentences that are joined without end punctuation: The event was exciting and It had music, a show and food.

Which figure of speech is used in this text? The moon is a friend for the lonesome to talk with. —Carl Sandburg, "Moonlight and Maggots"

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 personification, giving human characteristics to nonhuman things. The moon is a friend describes the moon as if it were human.

Select the organism in the same species as the North American beaver.

This organism is a North American beaver. Its scientific name is Castor canadensis.

closed choice

grade4

natural science

biology

Scientific names

Use scientific names to classify organisms

Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.

A North American beaver's scientific name is Castor canadensis. Ovis orientalis does not have the same scientific name as a North American beaver. So, Castor canadensis and Ovis orientalis are not in the same species. Alouatta caraya does not have the same scientific name as a North American beaver. So, Castor canadensis and Alouatta caraya are not in the same species. Castor canadensis has the same scientific name as a North American beaver. So, these organisms are in the same species.

Is corundum a mineral or a rock?

Corundum has the following properties: fixed crystal structure solid pure substance found in nature very hard not made by organisms

closed choice

grade8

natural science

earth-science

Rocks and minerals

Identify rocks and minerals

Minerals are the building blocks of rocks. A rock can be made of one or more minerals. Minerals and rocks have the following properties: Property | Mineral | Rock It is a solid. | Yes | Yes It is formed in nature. | Yes | Yes It is not made by organisms. | Yes | Yes It is a pure substance. | Yes | No It has a fixed crystal structure. | Yes | No You can use these properties to tell whether a substance is a mineral, a rock, or neither. Look closely at the last three properties: Minerals and rocks are not made by organisms. Organisms make their own body parts. For example, snails and clams make their shells. Because they are made by organisms, body parts cannot be minerals or rocks. Humans are organisms too. So, substances that humans make by hand or in factories are not minerals or rocks. A mineral is a pure substance, but a rock is not. A pure substance is made of only one type of matter. Minerals are pure substances, but rocks are not. Instead, all rocks are mixtures. A mineral has a fixed crystal structure, but a rock does not. The crystal structure of a substance tells you how the atoms or molecules in the substance are arranged. Different types of minerals have different crystal structures, but all minerals have a fixed crystal structure. This means that the atoms and molecules in different pieces of the same type of mineral are always arranged the same way. However, rocks do not have a fixed crystal structure. So, the arrangement of atoms or molecules in different pieces of the same type of rock may be different!

Corundum has all the properties of a mineral. So, corundum is a mineral.

What is the capital of Iowa?

closed choice

grade3

social science

geography

State capitals

Identify state capitals of the Midwest

Des Moines is the capital of Iowa.

Does this passage describe the weather or the climate?

Figure: Marseille. Marseille is a town on the southern coast of France. Cold winds from the north, called mistral winds, are common in Marseille each year during late winter and early spring. 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

grade5

natural science

earth-science

Weather and climate

Weather and climate around the world

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 passage carefully. Marseille is a town on the southern coast of France. Cold winds from the north, called mistral winds, are common in Marseille each year during late winter and early spring. The underlined part of the passage tells you about the usual wind patterns in Marseille. This passage does not describe what the weather is like on a particular day. So, this passage describes the climate.

Compare the motion of two motorboats. Which motorboat was moving at a higher speed?

closed choice

grade2

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 two objects moving for the same amount of time. The object that is moving faster will go a farther distance in that time. It is moving at a higher speed.

Look at the distance each motorboat moved and the time it took to move that distance. One motorboat moved 240 miles in 10 hours. The other motorboat moved 135 miles in 10 hours. Notice that each motorboat spent the same amount of time moving. The motorboat that moved 240 miles moved a farther distance in that time. So, that motorboat must have moved at a higher speed.

Which word would you find on a dictionary page with the following guide words? papoose - pliers

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 pedal is between the guide words papoose - pliers, it would be found on that page.

What is the capital of Virginia?

closed choice

grade4

social science

geography

State capitals

Identify state capitals of the Southeast

Richmond is the capital of Virginia.

Which property do these two objects have in common?

Select the better answer.

closed choice

grade2

natural science

physics

Materials

Compare properties of objects

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Different objects can have the same properties. You can use these properties to put objects into groups.

Look at each object. For each object, decide if it has that property. A sticky object can stick to other things. Neither of the objects are sticky. Yellow is a color. This color is yellow. Both objects are yellow. The property that both objects have in common is yellow.

Which sentence is more formal?

closed choice

grade8

language science

writing-strategies

Author's purpose and tone

Which sentence is more formal?

Formal writing is used for essays, business letters, and reports. The following types of informal language should be avoided in formal writing: Type | Examples slang | cool, awesome idioms | knock your socks off conversational language | gonna, kinda, yeah abbreviated language | ASAP, FYI overly simple or imprecise language | he got some stuff at the store contractions | can't, won't Contractions are not as informal as the other types, but they should be used sparingly in formal writing. Compare the following sentences. The first is informal. The second is formal. Informal: Yeah, ostriches can't fly, but they're awesome runners. Formal: Though ostriches are flightless, they are remarkably adept runners.

The first sentence is less formal. You can tell because it uses overly simple or imprecise language (took, went). The second sentence uses more precise language, so it is more formal overall.

What is the source of the allusion in the sentence below? When I learned the details of Lillian's Faustian bargain, I was in disbelief.

closed choice

grade7

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 Faustian bargain is literature. In a play by Christopher Marlowe based on the legend of Faust, a man strikes a deal with the devil. Disregarding the long-term consequences of his actions, he sells his soul in exchange for power. The allusion Faustian bargain means a compromise of one's values for personal gain.

How long does it take to bake lasagna in the oven?

Select the better estimate.

closed choice

grade3

natural science

units-and-measurement

Units and measurement

Choose units of time

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Imagine being told that the bus leaves in 7. You might be thinking, 7 what? Does the bus leave in 7 minutes? 7 seconds? The number 7 on its own does not give you much information about when the bus is leaving. That is because the units are missing. Time is usually measured in units of seconds, minutes, or hours. It takes about 1 second to sneeze and 1 minute to get dressed in the morning. It takes about 1 hour to bake a pie in the oven. There are 60 seconds in 1 minute. So, 1 second is much less than 1 minute. There are 60 minutes in 1 hour. So, 1 minute is much less than 1 hour.

The better estimate for how long it takes to bake lasagna in the oven is 42 minutes. 42 hours is too slow.

What is the capital of Idaho?

closed choice

grade3

social science

geography

State capitals

Identify the 50 state capitals

Boise is the capital of Idaho.

Is the following trait inherited or acquired? Most humans can sense many different smells.

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.

Babies do not need to learn how to smell. They are able to smell naturally. So, the ability to smell is an inherited trait.

Which correctly shows the title of a book?

closed choice

grade6

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 book should be in italics. The correct title is **Island of the Blue Dolphins**.

Complete the sentence. Lighting a match is a ().

closed choice

grade2

natural science

chemistry

Physical and chemical change

Identify physical and chemical changes

Chemical changes and physical changes are two ways matter can change. In a chemical change, the type of matter changes. Burning a piece of paper is a chemical change. The paper changes into ash and smoke. In a physical change, the type of matter stays the same. Cutting a piece of paper is a physical change. The cut pieces are still made of paper. Ice melting is also a physical change. When ice melts, it changes from a solid to a liquid. But both ice and liquid water are made of the same type of matter: water! This kind of change is called a change of state.

Lighting a match is a chemical change. The match catches fire and turns into ash. Ash is a different type of matter than the match.

Which property do these two objects have in common?

Select the better answer.

closed choice

grade2

natural science

physics

Materials

Compare properties of objects

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Different objects can have the same properties. You can use these properties to put objects into groups.

Look at each object. For each object, decide if it has that property. A breakable object will break into pieces if you drop it. Neither of the objects are breakable. A hard object keeps its shape when you squeeze it. Both objects are hard. The property that both objects have in common is hard.

Which ocean is highlighted?

closed choice

grade6

social science

geography

Physical Geography

Oceans and continents

Oceans are huge bodies of salt water. The world has five oceans. All of the oceans are connected, making one world ocean.

This is the Pacific Ocean.

Which of the following was an independent variable in this experiment?

The passage below describes an experiment. Read the passage and think about the variables that are described. Rick often saw woodpeckers perched in trees in his backyard, but he never saw them at his bird feeders. Rick usually filled his feeders with sunflower seeds. He wondered if he could attract woodpeckers by adding a different type of food to the feeders. To test this idea, Rick gathered eight identical bird feeders. He filled four with sunflower seeds. He filled the remaining four feeders with crushed peanuts. Rick then placed the bird feeders in his backyard. Over the next five days, he counted the number of woodpeckers that visited each bird feeder each morning. Hint: An independent variable is a variable whose effect you are investigating. A dependent variable is a variable that you measure. Figure: a woodpecker at a bird feeder.

closed choice

grade6

natural science

science-and-engineering-practices

Designing experiments

Identify independent and dependent variables

Experiments have variables, or parts that change. You can design an experiment to find out how one variable affects another variable. For example, imagine that you want to find out if fertilizer affects the number of tomatoes a tomato plant grows. To answer this question, you decide to set up two equal groups of tomato plants. Then, you add fertilizer to the soil of the plants in one group but not in the other group. Later, you measure the effect of the fertilizer by counting the number of tomatoes on each plant. In this experiment, the amount of fertilizer added to the soil and the number of tomatoes were both variables. The amount of fertilizer added to the soil was an independent variable because it was the variable whose effect you were investigating. This type of variable is called independent because its value does not depend on what happens after the experiment begins. Instead, you decided to give fertilizer to some plants and not to others. The number of tomatoes was a dependent variable because it was the variable you were measuring. This type of variable is called dependent because its value can depend on what happens in the experiment.

Which property matches this object?

Select the better answer.

closed choice

grade3

natural science

physics

Materials

Identify properties of an object

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.

Look at the object. Think about each property. A rough object feels scratchy when you touch it. The water slide is not rough. Blue is a color. This color is blue. The water slide is blue.

Select the vertebrate.

Hint: Mammals, birds, fish, reptiles, and amphibians are vertebrates.

closed choice

grade5

natural science

biology

Classification

Identify vertebrates and invertebrates

Vertebrates and invertebrates are both groups of animals. A vertebrate has a backbone. The backbone is made of many bones in an animal's back. A vertebrate's backbone helps connect the different parts of its body. In the drawings below, each vertebrate's backbone is colored orange. An invertebrate does not have a backbone. In fact, invertebrates do not have any bones! Some invertebrates have an outer cover on their body called an exoskeleton. Other invertebrates have a soft body.

A mosquito is an insect. Like other insects, a mosquito is an invertebrate. It does not have a backbone. It has an exoskeleton. A ladybug is an insect. Like other insects, a ladybug is an invertebrate. It does not have a backbone. It has an exoskeleton. An earthworm is a worm. Like other worms, an earthworm is an invertebrate. It does not have a backbone. It has a soft body. A rainbow trout is a fish. Like other fish, a rainbow trout is a vertebrate. It has a backbone.

Select the bird below.

Birds have feathers, two wings, and a beak. A woodpecker is an example of a bird.

closed choice

grade2

natural science

biology

Classification

Identify mammals, birds, fish, reptiles, and amphibians

Birds, mammals, fish, reptiles, and amphibians are groups of animals. The animals in each group have traits in common. Scientists sort animals into groups based on traits they have in common. This process is called classification.

An ostrich is a bird. It has feathers, two wings, and a beak. A Japanese tree frog is an amphibian. It has moist skin and begins its life in water.

Which announcement is more formal?

closed choice

grade11

language science

writing-strategies

Audience, purpose, and tone

Which text is most formal?

Informal writing is typically used in casual situations or when communicating with someone you know well. Informal language often expresses familiarity and tends to sound more like speech. It uses more conversational language, such as slang, idioms, abbreviations, imprecise language, and contractions. Formal writing is typically used in academic and business writing or when writing directly to an authority figure. It tends to be more courteous and impersonal, avoiding overly familiar or conversational language. Compare the following sentences. Informal: Yeah, ostriches can't fly, but I think they're awesome. More formal: Ostriches may be flightless, but they're remarkable runners. Most formal: Though flightless, ostriches are remarkable runners.

The second announcement is more formal. It uses more elevated language (pleased to announce). The other announcement sounds more conversational (so happy).

Will these magnets attract or repel each other?

Two magnets are placed as shown. Hint: Magnets that attract pull together. Magnets that repel push apart.

closed choice

grade2

natural science

physics

Magnets

Identify magnets that attract or repel

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. Whether a magnet attracts or repels other magnets depends on the positions of its poles, or ends. Every magnet has two poles, called north and south. Here are some examples of magnets. The north pole of each magnet is marked N, and the south pole is marked S. If different poles are closest to each other, the magnets attract. The magnets in the pair below attract. If the same poles are closest to each other, the magnets repel. The magnets in both pairs below repel.

Will these magnets attract or repel? To find out, look at which poles are closest to each other. The north pole of one magnet is closest to the south pole of the other magnet. Poles that are different attract. So, these magnets will attract each other.