Question: Which of these oceans does the prime meridian intersect?

Choices:
- the Atlantic Ocean
- the Indian Ocean
- the Pacific Ocean

social science

Lines of latitude and lines of longitude are imaginary lines drawn on some globes and maps. They can help you find places on globes and maps.
Lines of latitude show how far north or south a place is. We use units called degrees to describe how far a place is from the equator. The equator is the line located at 0° latitude. We start counting degrees from there.
Lines north of the equator are labeled N for north. Lines south of the equator are labeled S for south. Lines of latitude are also called parallels because each line is parallel to the equator.
Lines of longitude are also called meridians. They show how far east or west a place is. We use degrees to help describe how far a place is from the prime meridian. The prime meridian is the line located at 0° longitude. Lines west of the prime meridian are labeled W. Lines east of the prime meridian are labeled E. Meridians meet at the north and south poles.
The equator goes all the way around the earth, but the prime meridian is different. It only goes from the North Pole to the South Pole on one side of the earth. On the opposite side of the globe is another special meridian. It is labeled both 180°E and 180°W.
Together, lines of latitude and lines of longitude form a grid. You can use this grid to find the exact location of a place.

Solution: The prime meridian is the line at 0° longitude. It intersects the Atlantic Ocean. It does not intersect the Indian Ocean or the Pacific Ocean.


Question: Which trait does this red squirrel have?

Choices:
- It has fins.
- It has fur.

This image shows a Eurasian red squirrel.

natural science


Question: What can Kiara and Fernando trade to each get what they want?

Choices:
- Kiara can trade her tomatoes for Fernando's carrots.
- Fernando can trade his broccoli for Kiara's oranges.
- Kiara can trade her tomatoes for Fernando's broccoli.
- Fernando can trade his almonds for Kiara's tomatoes.

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.
Kiara and Fernando open their lunch boxes in the school cafeteria. Neither Kiara nor Fernando got everything that they wanted. The table below shows which items they each wanted:

Look at the images of their lunches. Then answer the question below.
Kiara's lunch Fernando's lunch

social science

Solution:
Look at the table and images.
Kiara wants broccoli. Fernando wants tomatoes. They can trade tomatoes for broccoli to both get what they want. Trading other things would not help both people get more items they want.


Question: What is the capital of North Dakota?

Choices:
- Fargo
- Bismarck
- Columbus
- Saint Louis

social science

Solution: Bismarck is the capital of North Dakota.


Question: Which of these states is farthest east?

Choices:
- Louisiana
- North Dakota
- North Carolina
- Arizona

social science

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.

Solution: To find the answer, look at the compass rose. Look at which way the east arrow is pointing. North Carolina is farthest east.


Question: Which continent is highlighted?

Choices:
- Australia
- Asia
- North America
- Antarctica

social science

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

Solution: This continent is Antarctica.


Question: What is the capital of Alaska?

Choices:
- Helena
- Juneau
- Olympia
- Fairbanks

social science

Solution: Juneau is the capital of Alaska.


Question: Which animal's neck is also adapted for hunting prey while keeping the rest of its body still?

Choices:
- northern pintail
- black-headed heron

Saddle-billed storks live near wetlands and lakes. They eat mostly fish.
The 's neck helps it grab fish while keeping the rest of its body still. If the stork had to move its body, it might scare the fish away.
Figure: saddle-billed stork.

natural science

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 an animal's neck is one example of an adaptation. Animals' necks can be adapted in different ways. For example, a large frilled neck might help an animal appear dangerous to its predators. A long neck might help an animal get food from tall trees.

Solution:
Look at the picture of the saddle-billed stork.
The saddle-billed stork has a long neck. Its neck is adapted for hunting prey while keeping the rest of its body still. This allows the saddle-billed stork to grab the prey without scaring it away.
Now look at each animal. Figure out which animal has a similar adaptation.
The black-headed heron has a long neck. Its neck is adapted for hunting prey while keeping the rest of its body still.
The northern pintail has a short neck. Its neck is not adapted for hunting prey while keeping the rest of its body still.


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

Choices:
- The magnitude of the magnetic force is greater in Pair 2.
- The magnitude of the magnetic force is greater in Pair 1.
- The magnitude of the magnetic force is the same in both pairs.

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.

natural science

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.

Solution:
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 1 than in Pair 2. So, the magnitude of the magnetic force is greater in Pair 1 than in Pair 2.


Question: Which of these states is farthest south?

Choices:
- Maine
- Massachusetts
- Michigan
- Delaware

social science

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.

Solution: To find the answer, look at the compass rose. Look at which way the south arrow is pointing. Delaware is farthest south.


Question: In this experiment, which were part of a control group?

Choices:
- the sections of wall scrubbed with water and baking soda
- the sections of wall scrubbed with water only

The passage below describes an experiment.

Luther's young son drew all over the living room wall with crayons! Luther wanted to find a way to remove the crayon markings. Based on what he read online, he decided to see if scrubbing a wall with baking soda could help remove crayon.
Luther dipped a sponge in water and used it to scrub the crayon on a small section of the wall. He dipped a second sponge in water, sprinkled it with baking soda, and used it to scrub the crayon on another section of the wall. He observed how much crayon was removed from each section. Luther repeated this test two more times on other sections of the wall.
Figure: scrubbing a crayon drawing off a wall.

natural science

Identify control and experimental groups

Experiments have variables, or parts that change. You can design an experiment to investigate whether changing a variable between different groups has a specific outcome.
For example, imagine you want to find out whether adding fertilizer to soil affects the height of pea plants. You could investigate this question with the following experiment:
You grow one group of pea plants in soil with fertilizer and measure the height of the plants. This group shows you what happens when fertilizer is added to soil. Since fertilizer is the variable whose effect you are investigating, this group is an experimental group.
You grow another group of pea plants in soil without fertilizer and measure the height of the plants. Since this group shows you what happens when fertilizer is not added to the soil, it is a control group.
By comparing the results from the experimental group to the results from the control group, you can conclude whether adding fertilizer to the soil affects pea plant height.

Solution: In this experiment, Luther investigated whether baking soda can remove crayon from a wall. The sections of wall scrubbed with water only did not get baking soda. So, they were part of a control group.


Question: What is the name of the colony shown?

Choices:
- Georgia
- New Hampshire
- South Carolina
- West Virginia

social science

Solution: The colony is Georgia.


Question: Which better describes the Okefenokee Swamp ecosystem?

Choices:
- It has land that is covered with water during most of the year. It also has soil that is rich in nutrients.
- It has soil that is poor in nutrients. It also has only a few types of organisms.

Figure: Okefenokee Swamp.
The Okefenokee Swamp is a wetland ecosystem in Georgia and Florida.

natural science

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

Solution: A wetland is a type of ecosystem. Wetlands have the following features: land that is covered with water during most of the year, soil that is rich in nutrients, and other water ecosystems nearby. So, the Okefenokee Swamp has land that is covered with water during most of the year. It also has soil that is rich in nutrients.


Question: Select the mammal below.

Choices:
- brown tree frog
- red crowned crane
- great white shark
- red kangaroo

Mammals have hair or fur and feed their young milk.
Mammals are warm-blooded. Warm-blooded animals can control their body temperature.
A koala is an example of a mammal.

natural science

Identify mammals, birds, fish, reptiles, and amphibians

Birds, mammals, fish, reptiles, and amphibians are groups of animals. Scientists sort animals into each group based on traits they have in common. This process is called classification.
Classification helps scientists learn about how animals live. Classification also helps scientists compare similar animals.

Solution:
A brown tree frog is an amphibian. It has moist skin and begins its life in water.
There are many kinds of tree frogs. Most tree frogs are very small. They can walk on thin branches.
A great white shark is a fish. It lives underwater. It has fins, not limbs.
Great white sharks can live for up to 70 years.
A red crowned crane is a bird. It has feathers, two wings, and a beak.
Cranes wade in shallow water to look for food. Cranes eat insects, worms, and plants.
A red kangaroo is a mammal. It has fur and feeds its young milk.
Kangaroos hop to move around. They use their large tails for balance while hopping.


Question: Which is this organism's common name?

Choices:
- Steller's sea eagle
- Haliaeetus pelagicus

This organism is Haliaeetus pelagicus. It is also called a Steller's sea eagle.

natural science

An organism's common name is the name that people normally call the organism. Common names often contain words you know.
An organism's scientific name is the name scientists use to identify the organism. Scientific names often contain words that are not used in everyday English.
Scientific names are written in italics, but common names are usually not. The first word of the scientific name is capitalized, and the second word is not. For example, the common name of the animal below is giant panda. Its scientific name is Ailuropoda melanoleuca.

Solution:
Haliaeetus pelagicus is written in italics. The first word is capitalized, and the second word is not. So, it is the scientific name.
Haliaeetus pelagicus is the organism's scientific name. So, you know that Steller's sea eagle is the common name.


Question: Which country is highlighted?

Choices:
- Saint Vincent and the Grenadines
- Saint Lucia
- Barbados
- Grenada

social science

Identify and select countries of the Caribbean

Solution: This country is Saint Vincent and the Grenadines.


Question: Which property do these three objects have in common?

Choices:
- shiny
- translucent
- soft

natural science

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.

Solution:
Look at each object.
For each object, decide if it has that property.
A shiny object reflects a lot of light. You can usually see your reflection in a shiny object. All three objects are shiny.
A soft object changes shape when pressed or squeezed. None of the objects are soft.
A translucent object lets light through. But you cannot see clearly through a translucent object. The sapphire is translucent, but the car bumper and the metal bar are not.
The property that all three objects have in common is shiny.


Question: What is the direction of this pull?

Choices:
- away from the first train car
- toward the first train car

There is a magnet on each of these toy train cars. Each magnet attracts the other with a magnetic force. The force from the first train car pulls the second train car along behind it.

natural science

A force is a push or a pull that one object applies to another. Every force has a direction.
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.

Solution: The magnet on the first train car pulls the second train car. The direction of the pull is toward the first train car.


Question: Which part of the orange tree makes the seeds?

Choices:
- the flowers
- the fruit

natural science

Describe and construct flowering plant life cycles

Many plants have flowers. These plants can use their flowers to reproduce, or make new plants like themselves. How do plants use their flowers to reproduce?
First, the male part of the flower makes pollen, and the female part makes eggs. Animals, wind, or water can move pollen. Pollination is what happens when pollen is moved to the female part of the flower.
After pollination, sperm from the pollen can combine with the eggs. This is called fertilization. The fertilized eggs grow into seeds. The fruit grows around the seeds. Later, a seed can fall out of the fruit. It can germinate, or start to grow into a new plant.

Solution:
Flowers make seeds. After a flower is pollinated, male cells from the pollen combine with eggs. This is called fertilization. The fertilized eggs grow into seeds.
The fruit can grow around the seeds. But the fruit does not make seeds. Both the fruit and the seeds grow from parts of the flower.


Question: Look at the models of molecules below. Select the elementary substance.

Choices:
- carbon tetrachloride
- nitrogen
- fluoromethanol

natural science

Identify elementary substances and compounds using models

There are more than 100 different chemical elements, or types of atoms. Chemical elements make up all of the substances around you.
A substance may be composed of one chemical element or multiple chemical elements. Substances that are composed of only one chemical element are elementary substances. Substances that are composed of multiple chemical elements bonded together are compounds.
Every chemical element is represented by its own atomic symbol. An atomic symbol may consist of one capital letter, or it may consist of a capital letter followed by a lowercase letter. For example, the atomic symbol for the chemical element boron is B, and the atomic symbol for the chemical element chlorine is Cl.
Scientists use different types of models to represent substances whose atoms are bonded in different ways. One type of model is a ball-and-stick model. The ball-and-stick model below represents a molecule of the compound boron trichloride.
In a ball-and-stick model, the balls represent atoms, and the sticks represent bonds. Notice that the balls in the model above are not all the same color. Each color represents a different chemical element. The legend shows the color and the atomic symbol for each chemical element in the substance.


Question: Which of these states is farthest north?

Choices:
- South Dakota
- New Mexico
- Nevada
- South Carolina

social science

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.

Solution: To find the answer, look at the compass rose. Look at which way the north arrow is pointing. South Dakota is farthest north.


Question: Which continent is highlighted?

Choices:
- South America
- Antarctica
- Asia
- Europe

social science

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

Solution: This continent is Asia.


Question: What can Marvin and Ken trade to each get what they want?

Choices:
- Marvin can trade his tomatoes for Ken's broccoli.
- Ken can trade his broccoli for Marvin's oranges.
- Ken can trade his almonds for Marvin's tomatoes.
- Marvin can trade his tomatoes for Ken's sandwich.

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.
Marvin and Ken open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Marvin wanted broccoli in his lunch and Ken was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.

social science

Solution:
Marvin wanted broccoli in his lunch and Ken was hoping for tomatoes. Look at the labeled part of the images.
Marvin has tomatoes. Ken 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.


Question: Identify the question that Maggie's experiment can best answer.

Choices:
- Do more tomato seedlings grow when they are planted in soil with fertilizer compared to soil without fertilizer?
- Does the humidity level where tomato seeds are planted affect the number of tomato seedlings that grow?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Maggie planted 25 tomato seeds one-half inch below the soil surface in each of six pots. Maggie added an equal amount of fertilizer to three of the six pots. She placed the pots in a plant growth chamber where all the seeds experienced the same temperature, amount of light, and humidity level. After two weeks, Maggie counted the number of seedlings that grew in each pot. She compared the number of seedlings in the pots with fertilizer to the number of seedlings in the pots without fertilizer.
Figure: tomato seedlings growing in soil.

natural science

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?


Question: Which country is highlighted?

Choices:
- Saint Kitts and Nevis
- Antigua and Barbuda
- Saint Vincent and the Grenadines
- Barbados

social science

Identify and select countries of the Caribbean

Solution: This country is Antigua and Barbuda.


Question: What is the capital of Massachusetts?

Choices:
- Annapolis
- Boston
- Baltimore
- Philadelphia

social science

Identify state capitals of the Northeast

Solution: Boston is the capital of Massachusetts.


Question: What is the name of the colony shown?

Choices:
- North Carolina
- Rhode Island
- Delaware
- Georgia

social science

Solution: The colony is Georgia.


Question: Which property do these three objects have in common?

Choices:
- bouncy
- blue
- fuzzy

natural science

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.

Solution:
Look at each object.
For each object, decide if it has that property.
Blue is a color.
This color is blue. All three objects are blue.
A fuzzy object is covered in soft hair. The water slide and the binder are not fuzzy.
A bouncy object will bounce back from the floor if you drop it. The jeans and the binder are not bouncy.
The property that all three objects have in common is blue.


Question: Which continent is highlighted?

Choices:
- Africa
- North America
- Europe
- Asia

social science

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

Solution: This continent is North America.


Question: What can Austin and Colin trade to each get what they want?

Choices:
- Colin can trade his broccoli for Austin's oranges.
- Colin can trade his almonds for Austin's tomatoes.
- Austin can trade his tomatoes for Colin's carrots.
- Austin can trade his tomatoes for Colin's broccoli.

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.
Austin and Colin open their lunch boxes in the school cafeteria. Neither Austin nor Colin got everything that they wanted. The table below shows which items they each wanted:

Look at the images of their lunches. Then answer the question below.
Austin's lunch Colin's lunch

social science

Solution:
Look at the table and images.
Austin wants broccoli. Colin wants tomatoes. They can trade tomatoes for broccoli to both get what they want. Trading other things would not help both people get more items they want.


Question: Which month is the hottest on average in Cape Town?

Choices:
- April, May, and November
- December, January, February, and March
- August, September, October, and November

Use the graph to answer the question below.

natural science

Scientists record climate data from places around the world. Temperature is one type of climate data. Scientists collect data over many years. They can use this data to calculate the average temperature for each month. The average temperature can be used to describe the climate of a location.
A line graph can be used to show the average temperature each month. Months with higher dots on the graph have higher average temperatures.

Solution:
To describe the average temperature trends in Cape Town, look at the graph.
Choice "Feb" is incorrect.
Choice "Mar" is incorrect.
Choice "Apr" is incorrect.
Choice "May" is incorrect.
Choice "Aug" is incorrect.
Choice "Sep" is incorrect.
Choice "Oct" is incorrect.
Choice "Nov" is incorrect.
Choice "Dec" is incorrect.
Choice "Jan" is incorrect.
The average temperatures in December, January, February, and March are around 20°C. These months have the highest average temperatures of all of the months. So, they are the hottest months on average.


Question: Look at the models of molecules below. Select the elementary substance.

Choices:
- silane
- nitrogen
- ethane

natural science

Identify elementary substances and compounds using models

There are more than 100 different chemical elements, or types of atoms. Chemical elements make up all of the substances around you.
A substance may be composed of one chemical element or multiple chemical elements. Substances that are composed of only one chemical element are elementary substances. Substances that are composed of multiple chemical elements bonded together are compounds.
Every chemical element is represented by its own atomic symbol. An atomic symbol may consist of one capital letter, or it may consist of a capital letter followed by a lowercase letter. For example, the atomic symbol for the chemical element boron is B, and the atomic symbol for the chemical element chlorine is Cl.
Scientists use different types of models to represent substances whose atoms are bonded in different ways. One type of model is a ball-and-stick model. The ball-and-stick model below represents a molecule of the compound boron trichloride.
In a ball-and-stick model, the balls represent atoms, and the sticks represent bonds. Notice that the balls in the model above are not all the same color. Each color represents a different chemical element. The legend shows the color and the atomic symbol for each chemical element in the substance.


Question: Select the organism in the same species as the great gray owl.

Choices:
- Strix nebulosa
- Goura victoria
- Cyanocitta cristata

This organism is a great gray owl. Its scientific name is Strix nebulosa.

natural science

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.

Solution:
A great gray owl's scientific name is Strix nebulosa.
Goura victoria does not have the same scientific name as a great gray owl. So, Strix nebulosa and Goura victoria are not in the same species.
Cyanocitta cristata does not have the same scientific name as a great gray owl. So, Strix nebulosa and Cyanocitta cristata are not in the same species.
Strix nebulosa has the same scientific name as a great gray owl. So, these organisms are in the same species.


Question: Identify the question that Ivan's experiment can best answer.

Choices:
- Can pennies hold more drops of water mixed with dish soap or water mixed with hand soap?
- Can pennies hold more drops of pure water or water mixed with hand soap?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Ivan used a dropper to put equal-sized drops of pure water, one at a time, onto a penny. The drops stayed together and formed a dome on the penny's surface. Ivan recorded the number of drops he could add before the water spilled over the edge of the penny. Then, he rinsed and dried the penny, and repeated the test using water mixed with hand soap. He repeated these trials on nine additional pennies. Ivan compared the average number of pure water drops to the average number of water drops mixed with hand soap that he could add to a penny before the water spilled over.
Figure: a dome of water on the surface of a penny.

natural science

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?


Question: Which property do these three objects have in common?

Choices:
- sticky
- opaque
- blue

natural science

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.

Solution:
Look at each object.
For each object, decide if it has that property.
An opaque object does not let light through. The caramel corn is opaque, but the tape is not.
A sticky object can attach or stick to other things. All three objects are sticky.
Blue is a color.
This color is blue. The cake batter and the caramel corn are not blue.
The property that all three objects have in common is sticky.


Question: Select the organism in the same species as the peregrine falcon.

Choices:
- Phoebastria nigripes
- Ardea alba
- Falco peregrinus

This organism is a peregrine falcon. Its scientific name is Falco peregrinus.

natural science

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.

Solution:
A peregrine falcon's scientific name is Falco peregrinus.
Phoebastria nigripes does not have the same scientific name as a peregrine falcon. So, Falco peregrinus and Phoebastria nigripes are not in the same species.
Falco peregrinus has the same scientific name as a peregrine falcon. So, these organisms are in the same species.
Ardea alba does not have the same scientific name as a peregrine falcon. So, Falco peregrinus and Ardea alba are not in the same species.


Question: In this food web, which organism contains matter that eventually moves to the earthworm?

Choices:
- mushroom
- barren-ground caribou
- lichen
- grizzly bear
- parasitic jaeger

Below is a food web from a tundra ecosystem in Nunavut, a territory in Northern Canada.
A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

natural science

A food web is a model.
A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food.
Arrows show how matter moves.
A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating.
An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web.
An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Solution:
Use the arrows to follow how matter moves through this food web. For each answer choice, try to find a path of arrows to the earthworm.
No arrows point from the mushroom to any other organisms. So, in this food web, matter does not move from the mushroom to the earthworm.
The only arrow pointing from the lichen leads to the barren-ground caribou. There are two arrows pointing from the barren-ground caribou to other organisms. One arrow points to the grizzly bear. The only arrow pointing from the grizzly bear leads to the mushroom. The other arrow pointing from the barren-ground caribou leads to the mushroom. No arrows point from the mushroom to any other organisms. So, in this food web, matter does not move from the lichen to the earthworm.
There are two arrows pointing from the barren-ground caribou to other organisms. One arrow points to the grizzly bear. The only arrow pointing from the grizzly bear leads to the mushroom. The other arrow pointing from the barren-ground caribou leads to the mushroom. No arrows point from the mushroom to any other organisms. So, in this food web, matter does not move from the barren-ground caribou to the earthworm.
The only arrow pointing from the grizzly bear leads to the mushroom. No arrows point from the mushroom to any other organisms. So, in this food web, matter does not move from the grizzly bear to the earthworm.There is one path matter can take from the parasitic jaeger to the earthworm: parasitic jaeger->rough-legged hawk->earthworm.


Question: Will these magnets attract or repel each other?

Choices:
- attract
- repel

Two magnets are placed as shown.

Hint: Magnets that attract pull together. Magnets that repel push apart.

natural science

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.

Solution:
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 north pole of the other magnet. Poles that are the same repel. So, these magnets will repel each other.


Question: Which animal's skin is better adapted as a warning sign to ward off predators?

Choices:
- crown-of-thorns sea star
- peppered moth

s have stinging cells in their brightly colored skin. The bright colors serve as a warning sign that the animal is toxic and dangerous. The 's skin is adapted to ward off predators.
Figure: Spanish shawl nudibranch.

natural science

Animal adaptations: skins and body coverings

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.

Solution:
Look at the picture of the Spanish shawl nudibranch.
The Spanish shawl nudibranch has stinging cells in its brightly colored skin. Its skin is adapted to ward off predators. The bright colors serve as a warning sign that the Spanish shawl nudibranch is toxic and dangerous.
Now look at each animal. Figure out which animal has a similar adaptation.
The crown-of-thorns sea star has venomous spines and brightly colored skin. Its skin is adapted to ward off predators.
The peppered moth has gray and brown patches on its body. Its skin is not adapted to be a warning sign that wards off predators.


Question: Which animal is also adapted for climbing trees?

Choices:
- chital
- lar gibbon

Crested black macaques live in the rain forests of Indonesia. They climb trees to find food and shelter. The macaque's hands and feet are adapted for climbing trees.
Figure: crested black macaque.

natural science

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of an animal's feet is one example of an adaptation. Animals' feet can be adapted in different ways. For example, webbed feet might help an animal swim. Feet with thick fur might help an animal walk on cold, snowy ground.

Solution:
Look at the picture of the crested black macaque.
The crested black macaque has long fingers and toes. It is adapted for climbing trees. The crested black macaque uses its long fingers and toes to hold on to branches while climbing.
Now look at each animal. Figure out which animal has a similar adaptation.
The lar gibbon has long fingers and toes. It is adapted for climbing trees.
The chital has four hoofed feet. It is not adapted for climbing trees. The chital uses its feet to walk and run.


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

Choices:
- sample B
- sample A
- neither; the samples have the same 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.

natural science

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.

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


Question: What is the name of the colony shown?

Choices:
- Iowa
- New Hampshire
- Vermont
- New York

social science

Solution:
The colony is New Hampshire.
During the colonial era, New Hampshire and New York both claimed the territory that would later become the state of Vermont. Vermont was never its own colony.


Question: Which month is the wettest on average in Christchurch?

Choices:
- December
- May
- April

Use the graph to answer the question below.

natural science

Scientists record climate data from places around the world. Precipitation, or rain and snow, is one type of climate data.
A bar graph can be used to show the average amount of precipitation each month. Months with taller bars have more precipitation on average.

Solution:
To describe the average precipitation trends in Christchurch, look at the graph.
Choice "Apr" is incorrect.
Choice "May" is incorrect.
Choice "Dec" is incorrect.
May has an average monthly precipitation of about 70 millimeters. This is higher than in any other month. So, May is the wettest month on average.


Question:
Is the following statement about our solar system true or false?
Earth is the largest planet that is made mainly of rock.

Choices:
- true
- false

Use the data to answer the question below.

natural science

Analyze data to compare properties of planets

A planet's volume tells you the size of the planet.
The primary composition of a planet is what the planet is made mainly of. In our solar system, planets are made mainly of rock, gas, or ice.

Solution: The table tells you that Mercury, Venus, Earth, and Mars are the planets made mainly of rock. Of these planets, Earth is the largest. So, Earth is the largest planet that is made mainly of rock.


Question: Which solution has a higher concentration of blue particles?

Choices:
- Solution B
- neither; their concentrations are the same
- Solution A

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

natural science

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

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


Question: What can Jonah and Cassie trade to each get what they want?

Choices:
- Cassie can trade her broccoli for Jonah's oranges.
- Jonah can trade his tomatoes for Cassie's carrots.
- Cassie can trade her almonds for Jonah's tomatoes.
- Jonah can trade his tomatoes for Cassie's broccoli.

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.
Jonah and Cassie open their lunch boxes in the school cafeteria. Neither Jonah nor Cassie got everything that they wanted. The table below shows which items they each wanted:

Look at the images of their lunches. Then answer the question below.
Jonah's lunch Cassie's lunch

social science

Solution:
Look at the table and images.
Jonah wants broccoli. Cassie wants tomatoes. They can trade tomatoes for broccoli to both get what they want. Trading other things would not help both people get more items they want.


Question: Which term matches the picture?

Choices:
- analogous structures
- homologous structure

Read the text.
Biologists can look at how related two animals are by comparing their body parts, or structures. Analogous structures are parts with the same purpose but with different structures, like a fin and a flipper. Different species may develop analogous structures when they live in similar environments even if they aren't closely related.
Homologous structures, however, may show that species are related by indicating they have common ancestors. A whale is a mammal, which makes it more closely related to a bear than to a fish, and a whale's flipper has bones like those in a bear's paw. Though they are different shapes and sizes, the arrangement of bones is similar.

language science

Determine the meaning of domain-specific words with pictures

Solution: Homologous structures have the same basic parts and suggest different species shared a common ancestor. A person's arm and a frog's arm are both made of a similar set of bones, even though the bones within a frog's arm are differently sized and shaped than those in a human's.


Question: What is the capital of South Dakota?

Choices:
- Laramie
- Bismarck
- Pierre
- Sioux Falls

social science

Solution: Pierre is the capital of South Dakota.


Question: Select the mammal below.

Choices:
- Japanese tree frog
- human

Mammals have hair or fur and feed their young milk. A sea otter is an example of a mammal.

natural science

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.

Solution:
A human is a mammal. It has hair and feeds its young milk.
Humans are a type of animal called a primate. Monkeys and apes are also primates.
A Japanese tree frog is an amphibian. It has moist skin and begins its life in water.
There are many kinds of tree frogs. Most tree frogs are very small. They can walk on thin branches.


Question: What is the capital of Tennessee?

Choices:
- Memphis
- Harrisburg
- Nashville
- Montgomery

social science

Identify state capitals of the Southeast

Solution: Nashville is the capital of Tennessee.


Question: What is the capital of Idaho?

Choices:
- Santa Fe
- Boise
- Topeka
- Madison

social science

Solution: Boise is the capital of Idaho.


Question: Which rhetorical appeal is primarily used in this ad?

Choices:
- logos (reason)
- ethos (character)
- pathos (emotion)

language science

Identify appeals to ethos, pathos, and logos in advertisements

The purpose of an advertisement is to persuade people to do something. To accomplish this purpose, advertisements use three types of persuasive strategies, or appeals.
Appeals to ethos, or character, show the writer or speaker as trustworthy, authoritative, or sharing important values with the audience. An ad that appeals to ethos might do one of the following:
say that a brand has been trusted for many years
include an endorsement from a respected organization, such as the American Dental Association
feature a testimonial from a "real person" who shares the audience's values
use an admired celebrity or athlete as a spokesperson
Appeals to logos, or reason, use logic and verifiable evidence. An ad that appeals to logos might do one of the following:
use graphs or charts to display information
cite results of clinical trials or independently conducted studies
explain the science behind a product or service
emphasize that the product is a financially wise choice
anticipate and refute potential counterclaims
Appeals to pathos, or emotion, use feelings rather than facts to persuade the audience. An ad that appeals to pathos might do one of the following:
trigger a fear, such as the fear of embarrassment
appeal to a desire, such as the desire to appear attractive
link the product to a positive feeling, such as adventure, love, or luxury

Solution: The ad appeals to pathos, or emotion, by evoking a fear of social exclusion.


Question: Based on the map, which of the following areas did the Mongol Empire control?

Choices:
- East Asia
- Southeast Asia
- South Asia

The Mongol Empire controlled most of Asia and some parts of Eastern Europe from around 1210 to 1375. Look at the map of the Mongol Empire. Then answer the question below.

social science

Solution:
Look back at the map. The labels on the map show the name of each region. The shaded area shows the territory controlled by the Mongol Empire.
The map shows that the Mongol Empire controlled many parts of East Asia, Central Asia, Siberia, and the Middle East.
The Mongol Empire did not control Southeast Asia or South Asia.


Question: Is shampoo a mineral?

Choices:
- yes
- no

Shampoo has the following properties:
not a pure substance
no fixed crystal structure
human-made
liquid

natural science

Properties are used to identify different substances. Minerals have the following properties:
It is a solid.
It is formed in nature.
It is not made by organisms.
It is a pure substance.
It has a fixed crystal structure.
If a substance has all five of these properties, then it is a mineral.
Look closely at the last three properties:
A mineral is 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.
Humans are organisms too. So, substances that humans make by hand or in factories cannot be minerals.
A mineral is a pure substance.
A pure substance is made of only one type of matter. All minerals are pure substances.
A mineral has a fixed crystal structure.
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 or molecules in different pieces of the same type of mineral are always arranged the same way.

Solution: Shampoo does not have all the properties of a mineral. So, shampoo is not a mineral.


Question: Which property do these three objects have in common?

Choices:
- flexible
- yellow
- fuzzy

natural science

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.

Solution:
Look at each object.
For each object, decide if it has that property.
A flexible object can be folded or bent without breaking easily. All three objects are flexible.
Yellow is a color.
This color is yellow. The rubber duck is yellow, but the trampoline and the metal paper clip are not.
A fuzzy object is covered in soft hair. None of the objects are fuzzy.
The property that all three objects have in common is flexible.


Question: Which better describes the Okavango Delta ecosystem?

Choices:
- It has soil that is rich in nutrients. It also has other water ecosystems nearby.
- It has soil that is poor in nutrients. It also has other water ecosystems nearby.

Figure: Okavango Delta.
The Okavango Delta is a wetland ecosystem in Botswana, a country in southern Africa.

natural science

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

Solution: A wetland is a type of ecosystem. Wetlands have the following features: land that is covered with water during most of the year, soil that is rich in nutrients, and other water ecosystems nearby. So, the Okavango Delta has soil that is rich in nutrients. It also has other water ecosystems nearby.


Question: In this experiment, which were part of a control group?

Choices:
- the steel squares soaked in salt water
- the steel squares soaked in salt water and vinegar

The passage below describes an experiment.

Jessica was using steel to make rusted sculptures. After building each sculpture, she caused it to rust by placing it in salt water for eight hours. Jessica wondered if steel would rust faster if she added vinegar to the salt water.
Jessica cut ten squares of steel sheet metal. She put five of the squares into a tub filled with salt water. She put the other five squares into a tub filled with salt water mixed with vinegar. Once an hour for eight hours, Jessica counted how many steel squares in each group had rust on them.
Figure: a sculpture made from rusted steel.

natural science

Identify control and experimental groups

Experiments have variables, or parts that change. You can design an experiment to investigate whether changing a variable between different groups has a specific outcome.
For example, imagine you want to find out whether adding fertilizer to soil affects the height of pea plants. You could investigate this question with the following experiment:
You grow one group of pea plants in soil with fertilizer and measure the height of the plants. This group shows you what happens when fertilizer is added to soil. Since fertilizer is the variable whose effect you are investigating, this group is an experimental group.
You grow another group of pea plants in soil without fertilizer and measure the height of the plants. Since this group shows you what happens when fertilizer is not added to the soil, it is a control group.
By comparing the results from the experimental group to the results from the control group, you can conclude whether adding fertilizer to the soil affects pea plant height.

Solution: In this experiment, Jessica investigated whether adding vinegar to salt water affects how quickly steel squares rust. The steel squares soaked in salt water did not get vinegar. So, they were part of a control group.


Question: Which solution has a higher concentration of yellow particles?

Choices:
- Solution A
- Solution B
- neither; their concentrations are the same

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

natural science

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

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


Question: Which animal's mouth is also adapted to get insects out of burrows?

Choices:
- aardvark
- brown hyena

Long-beaked echidnas eat animals such as insects. These insects often live in holes called burrows. The echidna's mouth is adapted to get insects out of burrows.
Figure: long-beaked echidna.

natural science

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 an animal's mouth is one example of an adaptation. Animals' mouths can be adapted in different ways. For example, a large mouth with sharp teeth might help an animal tear through meat. A long, thin mouth might help an animal catch insects that live in holes. Animals that eat similar food often have similar mouths.

Solution:
Look at the picture of the long-beaked echidna.
A tube-shaped snout helps the long-beaked echidna reach into a burrow. A long, sticky tongue helps it catch the insects.
Now look at each animal. Figure out which animal has a similar adaptation.
The aardvark has a tube-shaped mouth and a long, sticky tongue. Its mouth is adapted to eat insects that live inside burrows.
The brown hyena has a wide snout. Its mouth is not adapted to get insects out of burrows. The brown hyena uses its mouth to tear through meat.


Question: Which continent is highlighted?

Choices:
- Europe
- South America
- Africa
- North America

social science

A continent is one of the seven largest areas of land on earth.

Solution: This continent is South America.


Question: Which of these organisms contains matter that was once part of the phytoplankton?

Choices:
- orca
- sea cucumber
- sea urchin

Below is a food web from an ocean ecosystem in Monterey Bay, off the coast of California.
A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

natural science

A food web is a model.
A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food.
Arrows show how matter moves.
A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating.
An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web.
An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Solution: Use the arrows to follow how matter moves through this food web. For each answer choice, try to find a path of arrows that starts from the phytoplankton.There are two paths matter can take from the phytoplankton to the sea cucumber: phytoplankton->plainfin midshipman->sea cucumber. phytoplankton->zooplankton->plainfin midshipman->sea cucumber. There is one path matter can take from the phytoplankton to the black rockfish: phytoplankton->zooplankton->black rockfish. orca. The only arrow pointing to the orca starts from the sea otter. The only arrow pointing to the sea otter starts from the sea urchin. The only arrow pointing to the sea urchin starts from the kelp. No arrow points to the kelp. So, in this food web, matter does not move from the phytoplankton to the orca.. sea urchin. The only arrow pointing to the sea urchin starts from the kelp. No arrow points to the kelp. So, in this food web, matter does not move from the phytoplankton to the sea urchin..


Question: Which property matches this object?

Choices:
- translucent
- colorful

natural science

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.

Solution:
Look at the object.
Think about each property.
A colorful object has one or more bright colors. The wet ice cube is not colorful.
A translucent object lets light through. But you cannot see clearly through a translucent object. The wet ice cube is translucent.


Question: What is the capital of Hawaii?

Choices:
- Lincoln
- Honolulu
- Hilo
- Juneau

social science

Solution: Honolulu is the capital of Hawaii.


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

Choices:
- The strength of the magnetic force is the same in both pairs.
- The magnetic force is stronger in Pair 1.
- The magnetic force is stronger in Pair 2.

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.

natural science

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.

Solution:
Distance affects the strength of the magnetic force. But the distance between the magnets in Pair 1 and in Pair 2 is the same.
So, the strength of the magnetic force is the same in both pairs.


Question: Which country is highlighted?

Choices:
- Solomon Islands
- New Zealand
- the Federated States of Micronesia
- Papua New Guinea

social science

Identify and select countries of Oceania

Solution:
This country is Papua New Guinea.
Why does Papua New Guinea share its island with another country?
Papua New Guinea takes up the eastern half of the island of New Guinea. The western half is part of Indonesia, an Asian country.
Beginning in the 17 th century, several countries took control of different parts of the island of New Guinea. By 1922, Australia controlled the entire eastern half of the island, and the Netherlands controlled the western half. In 1963, control over the western half was transferred to Indonesia, which had just gained independence from the Netherlands. Many people in western New Guinea did not want to become part of Indonesia, though, and some people in this area are still fighting to leave Indonesia today. The eastern part gained independence from Australia in 1975 and became Papua New Guinea.


Question: Which of these states is farthest north?

Choices:
- Colorado
- Arkansas
- Idaho
- South Carolina

social science

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.

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


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

Choices:
- neither; the samples have the same temperature
- sample A
- sample B

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.

natural science

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.

Solution:
Each particle in sample B has more mass than each particle in sample A. The particles in sample B also have a higher average speed than the particles in sample A. So, the particles in sample B have a higher average kinetic energy than the particles in sample A.
Because the particles in sample B have the higher average kinetic energy, sample B must have the higher temperature.


Question:
Is the following statement about our solar system true or false?
The smallest planet is made mainly of rock.

Choices:
- false
- true

Use the data to answer the question below.

natural science

Analyze data to compare properties of planets

A planet's volume tells you the size of the planet.
The primary composition of a planet is what the planet is made mainly of. In our solar system, planets are made mainly of rock, gas, or ice.

Solution: The table tells you that the smallest planet is Mercury and that Mercury is made mainly of rock. So, the smallest planet is made mainly of rock.


Question: What is the capital of Michigan?

Choices:
- Pierre
- Charleston
- Grand Rapids
- Lansing

social science

Solution: Lansing is the capital of Michigan.


Question: Which better describes the Serengeti National Park ecosystem?

Choices:
- It has a rainy season and a dry season. It also has long, cold winters.
- It has warm summers and warm winters. It also has soil that is poor in nutrients.

Figure: Serengeti National Park.
Serengeti National Park is a savanna grassland ecosystem in Tanzania, a country in eastern Africa.

natural science

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

Solution: A savanna grassland is a type of ecosystem. Savanna grasslands have the following features: warm summers and warm winters, a rainy season and a dry season, and soil that is poor in nutrients. So, Serengeti National Park has warm summers and warm winters. It also has soil that is poor in nutrients.


Question: What is the name of the colony shown?

Choices:
- Virginia
- New York
- Delaware
- Vermont

social science

Solution:
The colony is New York.
During the colonial era, New Hampshire and New York both claimed the territory that would later become the state of Vermont. Vermont was never its own colony.


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

Choices:
- The magnitude of the magnetic force is the same in both pairs.
- The magnitude of the magnetic force is smaller in Pair 1.
- The magnitude of the magnetic force is smaller in Pair 2.

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.

natural science

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.

Solution:
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.


Question: What is the name of the colony shown?

Choices:
- New York
- Connecticut
- New Hampshire
- Massachusetts

social science

Solution: The colony is Connecticut.


Question: Which animal's limbs are also adapted for climbing trees?

Choices:
- okapi
- Sumatran orangutan

Chimpanzees live in the forests of Central Africa. Their limbs are adapted for climbing trees.
Figure: chimpanzee.

natural science

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
Arms, legs, flippers, and wings are different types of limbs. The type of limbs an animal has is an example of an adaptation. Animals' limbs can be adapted in different ways. For example, long legs might help an animal run fast. Flippers might help an animal swim. Wings might help an animal fly.

Solution:
Look at the picture of the chimpanzee.
The chimpanzee uses its long limbs to reach branches while climbing. It uses its fingers and toes to grab the branches.
Now look at each animal. Figure out which animal has a similar adaptation.
The Sumatran orangutan has long limbs with fingers and toes. Its limbs are adapted for climbing trees.
The okapi has long, thin limbs. Its limbs are not adapted for climbing trees. The okapi uses its limbs for walking and running.


Question: Which animal is also adapted to be camouflaged among dead leaves?

Choices:
- plated leaf chameleon
- Arctic wolf

Dead leaf mantises are found in forests. The mantis is adapted to be camouflaged among dead leaves.
Figure: dead leaf mantis.

natural science

Animal adaptations: skins and body coverings

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.

Solution:
Look at the picture of the dead leaf mantis.
The dead leaf mantis has a reddish-brown body. It is adapted to be camouflaged among dead leaves, which often have a reddish or brownish color. The word camouflage means to blend in.
Now look at each animal. Figure out which animal has a similar adaptation.
The plated leaf chameleon has reddish-brown scales coverings its body. It is adapted to be camouflaged among dead leaves, which often have a reddish or brownish color.
This Arctic wolf has white fur covering its body. It is not adapted to be camouflaged among dead leaves.


Question: What is the capital of Connecticut?

Choices:
- Spokane
- Bridgeport
- New Haven
- Hartford

social science

Identify state capitals of the Northeast

Solution: Hartford is the capital of Connecticut.


Question: Identify the question that Janelle's experiment can best answer.

Choices:
- Do radish plants grown under bright light have more leaves than radish plants grown under dim light?
- Do radishes grown under bright light get bigger than radishes grown under dim light?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Janelle planted 20 radish plants in a greenhouse, putting each plant in its own pot. She placed ten of the pots under bright light and the other ten pots under dim light. Janelle watered all the plants twice a day. After two months, she pulled the radish plants from the ground, threw away the leafy green tops, and measured the sizes of the radishes. She compared the sizes of the radishes grown under bright light to the sizes of the radishes grown under dim light.
Figure: a radish plant in soil.

natural science

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?


Question: Which continent is highlighted?

Choices:
- Antarctica
- Africa
- South America
- Europe

social science

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

Solution: This continent is South America.


Question: How does thick fur help animals in wintertime?

Choices:
- It keeps them warm by trapping their body heat.
- It makes them look older.

Read the passage about winter coats.
People put on winter coats when it's cold outside, and some animals have winter coats, too! They grow extra-thick coats of fur to keep warm in winter. The thick fur traps their body heat and keeps it close to their skin. Many wild animals grow winter coats. But so do some cats and dogs.
Some animals, like arctic foxes, also change coat colors in winter. They shed their brown fur and grow thick white coats. Their white coats help them hide from other animals in the snow.

language science

Read and understand informational passages

Solution:
Look at the passage. It tells you how thick fur helps animals in wintertime.
People put on winter coats when it's cold outside, and some animals have winter coats, too! They grow extra-thick coats of fur to keep warm in winter. The thick fur traps their body heat and keeps it close to their skin. Many wild animals grow winter coats. But so do some cats and dogs.


Question: Select the organism in the same genus as the axolotl.

Choices:
- Python reticulatus
- Tigrisoma mexicanum
- Ambystoma opacum

This organism is an axolotl. Its scientific name is Ambystoma mexicanum.

natural science

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.

Solution:
An axolotl's scientific name is Ambystoma mexicanum. The first word of its scientific name is Ambystoma.
Python reticulatus is in the genus Python. The first word of its scientific name is Python. So, Python reticulatus and Ambystoma mexicanum are not in the same genus.
Ambystoma opacum is in the genus Ambystoma. The first word of its scientific name is Ambystoma. So, Ambystoma opacum and Ambystoma mexicanum are in the same genus.
Tigrisoma mexicanum and Ambystoma mexicanum are not in the same genus.
These organisms are not in the same genus, but part of their scientific names is the same. Tigrisoma mexicanum and Ambystoma mexicanum have the same species name within their genus, mexicanum. But the first words of their scientific names are different. Tigrisoma mexicanum is in the genus Tigrisoma, and Ambystoma mexicanum is in the genus Ambystoma.


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

Choices:
- crocodile egg
- palm leaf

This diagram shows fossils in an undisturbed sedimentary rock sequence.

natural science

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.

Solution:
Look again at the fossils in the rock sequence diagram.
Compare the positions of these fossils to determine which one is older:
The palm leaf fossil is in a deeper layer in the rock sequence than the crocodile egg fossil. So, the palm leaf fossil is most likely older than the crocodile egg fossil.


Question: Select the amphibian below.

Choices:
- poison dart frog
- helmeted iguana

Amphibians have moist skin and begin their lives in water. A golden frog is an example of an amphibian.

natural science

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.

Solution:
A helmeted iguana is a reptile. It has scaly, waterproof skin.
Iguanas are a type of lizard. Iguanas eat plants and fruit.
A poison dart frog is an amphibian. It has moist skin and begins its life in water.
Poison dart frogs come in many bright colors. Their bright color warns other animals that these frogs are poisonous.


Question: Which country is highlighted?

Choices:
- Saint Kitts and Nevis
- Barbados
- Haiti
- Antigua and Barbuda

social science

Identify and select countries of the Caribbean

Solution: This country is Antigua and Barbuda.


Question: Which statement describes the Cerrado ecosystem?

Choices:
- It has warm summers and warm winters.
- It has a small amount of rain.

Figure: Cerrado.
The savanna grasslands of Brazil are called the Cerrado. The Cerrado covers over one-fifth of Brazil and is home to termites, anteaters, armadillos, and other organisms.

natural science

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

Solution: A savanna grassland is a type of ecosystem. Savanna grasslands have the following features: warm summers and warm winters, a rainy season and a dry season, and soil that is poor in nutrients. So, the following statements describe the Cerrado ecosystem: warm summers and warm winters, a rainy season and a dry season, and soil that is poor in nutrients. It has a rainy season and a dry season. It has warm summers and warm winters. The following statement does not describe the Cerrado: warm summers and warm winters, a rainy season and a dry season, and soil that is poor in nutrients. It has a small amount of rain.


Question: What is the probability that a muskmelon plant produced by this cross will be homozygous recessive for the fruit taste gene?

Choices:
- 2/4
- 1/4
- 0/4
- 3/4
- 4/4

In a group of muskmelon plants, some individuals have sour fruit and others have sweet fruit. In this group, the gene for the fruit taste trait has two alleles. The allele for sweet fruit (f) is recessive to the allele for sour fruit (F).
This Punnett square shows a cross between two muskmelon plants.

natural science

Use Punnett squares to calculate probabilities of offspring types

Offspring genotypes: homozygous or heterozygous?
How do you determine whether an organism is homozygous or heterozygous for a gene? Look at the alleles in the organism's genotype for that gene.
An organism with two identical alleles for a gene is homozygous for that gene.
If both alleles are dominant, the organism is homozygous dominant for the gene.
If both alleles are recessive, the organism is homozygous recessive for the gene.
An organism with two different alleles for a gene is heterozygous for that gene.
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


Question: What can Jaylen and Porter trade to each get what they want?

Choices:
- Jaylen can trade his tomatoes for Porter's broccoli.
- Porter can trade his almonds for Jaylen's tomatoes.
- Jaylen can trade his tomatoes for Porter's sandwich.
- Porter can trade his broccoli for Jaylen's oranges.

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.
Jaylen and Porter open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Jaylen wanted broccoli in his lunch and Porter was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.

social science

Solution:
Jaylen wanted broccoli in his lunch and Porter was hoping for tomatoes. Look at the labeled part of the images.
Jaylen has tomatoes. Porter 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.


Question: Which property do these three objects have in common?

Choices:
- rough
- soft
- transparent

natural science

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.

Solution:
Look at each object.
For each object, decide if it has that property.
You can see clearly through a transparent object. None of the objects are transparent.
A rough object feels scratchy when you touch it. All three objects are rough.
A soft object changes shape when pressed or squeezed. None of the objects are soft.
The property that all three objects have in common is rough.


Question: Which country is highlighted?

Choices:
- Nauru
- the Federated States of Micronesia
- the Marshall Islands
- Samoa

social science

Identify and select countries of Oceania

Solution: This country is Nauru.


Question: Which animal's feet are also adapted for grabbing prey?

Choices:
- Malayan tapir
- common buzzard

Golden eagles eat fish, mammals, and other birds. The 's feet are adapted to grab prey.
Figure: golden eagle.

natural science

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of an animal's feet is one example of an adaptation. Animals' feet can be adapted in different ways. For example, webbed feet might help an animal swim. Feet with thick fur might help an animal walk on cold, snowy ground.

Solution:
Look at the picture of the golden eagle.
The golden eagle has long toes with sharp claws. Its feet are adapted for grabbing prey. The sharp claws can help the golden eagle attack and kill its prey. The long toes can help it hold on to its prey.
Now look at each animal. Figure out which animal has a similar adaptation.
The common buzzard has long toes with sharp claws. Its feet are adapted for grabbing prey.
The Malayan tapir has large, heavy feet. Its feet are not adapted for grabbing prey. The Malayan tapir uses its feet to walk and run.


Question: What is the capital of Pennsylvania?

Choices:
- Harrisburg
- Dover
- Montpelier
- Concord

social science

Identify state capitals of the Northeast

Solution: Harrisburg is the capital of Pennsylvania.


Question: Which rock layer is older?

Choices:
- the limestone layer
- the sandstone layer

The following diagram shows an example of a rock sequence. Use the rock sequence to answer the question below.

natural science

Interpret evidence from fossils in rock layers

Solution:
Look at the diagram of the rock sequence. The double-headed arrow on the left tells you how the rock layers are arranged by age. In this diagram, the older layer is shown below the younger layer.
The sandstone layer is older than the limestone layer.


Question: Which of these states is farthest north?

Choices:
- New Mexico
- New York
- Indiana
- Delaware

social science

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.

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


Question: What is the capital of Massachusetts?

Choices:
- Albany
- Annapolis
- Cambridge
- Boston

social science

Identify state capitals of the Northeast

Solution: Boston is the capital of Massachusetts.


Question:
Complete the text to describe the diagram.
Solute particles moved in both directions across the permeable membrane. But more solute particles moved across the membrane (). When there was an equal concentration on both sides, the particles reached equilibrium.

Choices:
- to the left than to the right
- to the right than to the left

The diagram below shows a solution with one solute. Each solute particle is represented by a green ball. The solution fills a closed container that is divided in half by a membrane. The membrane, represented by a dotted line, is permeable to the solute particles.
The diagram shows how the solution can change over time during the process of diffusion.

natural science

In a solution, solute particles move and spread throughout the solvent. The diagram below shows how a solution can change over time. Solute particles move from the area where they are at a higher concentration to the area where they are at a lower concentration. This movement happens through the process of diffusion.
As a result of diffusion, the concentration of solute particles becomes equal throughout the solution. When this happens, the solute particles reach equilibrium. At equilibrium, the solute particles do not stop moving. But their concentration throughout the solution stays the same.
Membranes, or thin boundaries, can divide solutions into parts. A membrane is permeable to a solute when particles of the solute can pass through gaps in the membrane. In this case, solute particles can move freely across the membrane from one side to the other.
So, for the solute particles to reach equilibrium, more particles will move across a permeable membrane from the side with a higher concentration of solute particles to the side with a lower concentration. At equilibrium, the concentration on both sides of the membrane is equal.

Solution:
Look at the diagram again. It shows you how the solution changed during the process of diffusion.
Before the solute particles reached equilibrium, there were 3 solute particles on the left side of the membrane and 5 solute particles on the right side of the membrane.
When the solute particles reached equilibrium, there were 4 solute particles on each side of the membrane. There was 1 more solute particle on the left side of the membrane than before.
So, for the solute particles to reach equilibrium, more solute particles must have moved across the membrane to the left than to the right.


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

Choices:
- The magnitude of the magnetic force is the same in both pairs.
- The magnitude of the magnetic force is smaller in Pair 2.
- The magnitude of the magnetic force is smaller in Pair 1.

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.

natural science

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.

Solution:
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.


Question: What is the name of the colony shown?

Choices:
- Rhode Island
- Indiana
- New Hampshire
- Massachusetts

social science

Solution:
The colony is Massachusetts.
The Massachusetts Colony included land that would later become the state of Maine. Maine was never its own colony.


Question: Which of the following organisms is the primary consumer in this food web?

Choices:
- orca
- phytoplankton
- sea urchin
- black rockfish

Below is a food web from an ocean ecosystem in Monterey Bay, off the coast of California.
A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

natural science

A food web is a model.
A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food.
Arrows show how matter moves.
A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating.
An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web.
An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Solution:
Primary consumers eat producers. So, in a food web, primary consumers have arrows pointing to them from producers.
The black rockfish has an arrow pointing to it from the zooplankton. The zooplankton is not a producer. So, the black rockfish is not a primary consumer.
The phytoplankton does not have any arrows pointing to it. So, the phytoplankton is not a primary consumer.
The orca has an arrow pointing to it from the sea otter. The sea otter is not a producer. So, the orca is not a primary consumer.
The sea urchin has an arrow pointing to it from the kelp. The kelp is a producer, so the sea urchin is a primary consumer.
The kelp bass has an arrow pointing to it from the kelp. The kelp is a producer, so the kelp bass is a primary consumer.


Question: What is the capital of Tennessee?

Choices:
- Oklahoma City
- Knoxville
- Nashville
- Boise

social science

Identify state capitals of the Southeast

Solution: Nashville is the capital of Tennessee.


Question: Which country is highlighted?

Choices:
- Solomon Islands
- Tonga
- Fiji
- Vanuatu

social science

Identify and select countries of Oceania

Solution: This country is Fiji.


Question: What is the capital of Colorado?

Choices:
- Denver
- Boulder
- Olympia
- Tallahassee

social science

Solution: Denver is the capital of Colorado.


Question: Which solution has a higher concentration of blue particles?

Choices:
- neither; their concentrations are the same
- Solution A
- Solution B

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

natural science

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

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


Question:
Is the following statement about our solar system true or false?
The smallest planet is made mainly of rock.

Choices:
- false
- true

Use the data to answer the question below.

natural science

Analyze data to compare properties of planets

A planet's volume tells you the size of the planet.
The primary composition of a planet is what the planet is made mainly of. In our solar system, planets are made mainly of rock, gas, or ice.
The volume of a planet is a very large quantity. Large quantities such as this are often written in scientific notation.
For example, the volume of Jupiter is 1,430,000,000,000,000 km^3. In scientific notation, Jupiter's volume is written as 1.43 x 10^15 km^3.
To compare two numbers written in scientific notation, compare their exponents. The bigger the exponent is, the bigger the number is. For example:
1.43 x 10^15 is larger than 1.43 x 10^12
If their exponents are equal, compare the first numbers. For example:
1.43 x 10^15 is larger than 1.25 x 10^15

Solution:
To decide which planet is the smallest, look at the volumes shown in the table and compare the exponents. Mercury's volume has an exponent of 10, which is the smallest out of all the planets.
Mercury is made mainly of rock. So, the smallest planet is made mainly of rock.