Question: Select the organism in the same genus as the common kestrel.

Choices:
- Falco novaeseelandiae
- Ardea goliath
- Haliaeetus pelagicus

This organism is a common kestrel. Its scientific name is Falco tinnunculus.

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 common kestrel's scientific name is Falco tinnunculus. The first word of its scientific name is Falco.
Ardea goliath is in the genus Ardea. The first word of its scientific name is Ardea. So, Ardea goliath and Falco tinnunculus are not in the same genus.
Falco novaeseelandiae is in the genus Falco. The first word of its scientific name is Falco. So, Falco novaeseelandiae and Falco tinnunculus are in the same genus.
Haliaeetus pelagicus is in the genus Haliaeetus. The first word of its scientific name is Haliaeetus. So, Haliaeetus pelagicus and Falco tinnunculus are not in the same genus.


Question: Which of these cities is marked on the map?

Choices:
- Atlanta
- Los Angeles
- New York City
- Houston

social science

Solution: The city is Los Angeles, California. Atlanta, Houston, and New York City are marked with gray circles on the map below.


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 the two samples has the same mass, and the particles in both samples have the same average speed. So, the particles in both samples have the same average kinetic energy.
Because the particles in both samples have the same average kinetic energy, the samples must have the same temperature.


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

Choices:
- sea otter
- kelp bass
- black rockfish
- bat star

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:
Decomposers help break down dead organisms into simpler matter, such as nutrients. These nutrients can then help plants and other organisms grow. In a food web, there is an arrow pointing from another organism to a decomposer. There are no arrows pointing from a decomposer to another organism.
The bat star does not have arrows pointing from it to other organisms. So, the bat star is a decomposer.
The sea otter has an arrow pointing from it. So, the sea otter is not a decomposer.
The kelp bass has an arrow pointing from it. So, the kelp bass is not a decomposer.
The sea cucumber does not have arrows pointing from it to other organisms. So, the sea cucumber is a decomposer.
The black rockfish has an arrow pointing from it. So, the black rockfish is not a decomposer.


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

Choices:
- fluoromethanol
- tetraphosphorus
- methane

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: Will these magnets attract or repel each other?

Choices:
- repel
- attract

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 air temperature was measured within the outlined area shown?

Choices:
- -24°C
- 3°C
- -4°C

The map below shows air temperatures in the lower atmosphere on April 19, 2016. The outlined area shows an air mass that influenced weather in North America on that day.
Look at the map. Then, answer the question below.
Data source: United States National Oceanic and Atmospheric Administration/Earth System Research Laboratory, Physical Sciences Division

natural science

To study air masses, scientists can use maps that show conditions within Earth's atmosphere. For example, the map below uses color to show air temperatures.
The map's legend tells you the temperature that each color represents. Colors on the left in the legend represent lower temperatures than colors on the right. For example, areas on the map that are the darkest shade of blue have a temperature from -25°C up to -20°C. Areas that are the next darkest shade of blue have a temperature from -20°C up to -15°C.

Solution:
Look at the colors shown within the outlined area. Then, use the legend to determine which air temperatures those colors represent.
15°C.
-24°C is within this range.
-4°C and 3°C are outside of this range.


Question: Which country is highlighted?

Choices:
- Tonga
- Nauru
- the Federated States of Micronesia
- Samoa

social science

Identify and select countries of Oceania

Solution: This country is Samoa.


Question: What is the capital of Minnesota?

Choices:
- New Haven
- Saint Paul
- Dover
- Colorado Springs

social science

Solution: Saint Paul is the capital of Minnesota.


Question: Which material is this rocking chair made of?

Choices:
- wood
- silk

natural science

A material is a type of matter. Wood, glass, metal, and plastic are common materials.

Solution:
Look at the picture of the rocking chair.
The chair is made of wood.
Chairs are not always made of wood. Chairs can also be made of plastic or metal. Some chairs are made of several different materials. Are you sitting on a chair? If so, what is it made of?


Question: What is the capital of Alabama?

Choices:
- Montgomery
- Columbus
- Oklahoma City
- Birmingham

social science

Identify state capitals of the Southeast

Solution: Montgomery is the capital of Alabama.


Question: What is this archosaur's scientific name?

Choices:
- Effigia okeeffeae
- Effigia nesbitti

This drawing shows a type of archosaur, a dinosaur that grew to be about six feet long. This archosaur's fossil was discovered in rock near the Ghost Ranch Quarry in New Mexico. It was named after the painter Georgia O'Keeffe because she lived nearby.

natural science

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

Solution:
This organism's scientific name refers to Georgia O'Keeffe.
The word okeeffeae refers to Georgia O'Keeffe. So, this archosaur's scientific name is Effigia okeeffeae.


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

Choices:
- Do bananas develop more brown spots when they are kept at room temperature compared to in a cold refrigerator?
- Do bananas develop more brown spots if they are kept in bags with holes compared to bags without holes?

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

Stanley divided 40  evenly among eight paper bags and sealed the bags. He poked 20 small holes in four of the bags and left the other four without holes. He kept the bags at room temperature for three days. Then, Stanley opened the bags and counted the number of brown spots on each banana. He compared the average number of brown spots on bananas from bags with holes to the average number of brown spots on bananas from bags without holes.
Figure: unripe bananas.

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: 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 smaller in Pair 1.
- The magnitude of the magnetic force is the same in both pairs.
- 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 and 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 using magnets of different sizes. The magnitude of the magnetic force is smaller when the magnets are smaller.

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

Choices:
- ginkgo leaf
- insect

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 ginkgo leaf fossil is in a deeper layer in the rock sequence than the insect fossil. So, the ginkgo leaf fossil is most likely older than the insect fossil.


Question: Which state is highlighted?

Choices:
- South Dakota
- Kansas
- Illinois
- Michigan

social science

Solution: This state is South Dakota.


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

Choices:
- Arctic fox
- barren-ground caribou
- bilberry

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 that starts from the bear sedge.
The only arrow pointing to the barren-ground caribou starts from the lichen. No arrow points to the lichen. So, in this food web, matter does not move from the bear sedge to the barren-ground caribou.
No arrow points to the bilberry. So, in this food web, matter does not move from the bear sedge to the bilberry.


Question: What is the capital of Utah?

Choices:
- Salt Lake City
- Denver
- Des Moines
- Provo

social science

Solution: Salt Lake City is the capital of Utah.


Question: Which country is highlighted?

Choices:
- Haiti
- Dominica
- the Dominican Republic
- Trinidad and Tobago

social science

Identify and select countries of the Caribbean

Solution: This country is Dominica.


Question: Which of these states is farthest south?

Choices:
- Colorado
- Montana
- Washington
- Pennsylvania

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. Colorado is farthest south.


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 right than to the left
- to the left than to the right

The diagram below shows a solution with one solute. Each solute particle is represented by a pink 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 7 solute particles on the right side of the membrane.
When the solute particles reached equilibrium, there were 5 solute particles on each side of the membrane. There were 2 more solute particles 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: Which of the following could Robert's test show?

Choices:
- how steady a parachute with a 1 m vent was at 200 km per hour
- if the spacecraft was damaged when using a parachute with a 1 m vent going 200 km per hour
- whether a parachute with a 1 m vent would swing too much at 400 km per hour

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design.
The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below.

Robert was an aerospace engineer who was developing a parachute for a spacecraft that would land on Mars. He needed to add a vent at the center of the parachute so the spacecraft would land smoothly. However, the spacecraft would have to travel at a high speed before landing. If the vent was too big or too small, the parachute might swing wildly at this speed. The movement could damage the spacecraft.
So, to help decide how big the vent should be, Robert put a parachute with a 1 m vent in a wind tunnel. The wind tunnel made it seem like the parachute was moving at 200 km per hour. He observed the parachute to see how much it swung.
Figure: a spacecraft's parachute in a wind tunnel.

natural science

Evaluate tests of engineering-design solutions

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


Question: Select the organism in the same species as the Christmas tree worm.

Choices:
- Nerodia clarkii
- Spirobranchus giganteus
- Nerodia cyclopion

This organism is a Christmas tree worm. Its scientific name is Spirobranchus giganteus.

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 Christmas tree worm's scientific name is Spirobranchus giganteus.
Nerodia clarkii does not have the same scientific name as a Christmas tree worm. So, Spirobranchus giganteus and Nerodia clarkii are not in the same species.
Nerodia cyclopion does not have the same scientific name as a Christmas tree worm. So, Spirobranchus giganteus and Nerodia cyclopion are not in the same species.
Spirobranchus giganteus has the same scientific name as a Christmas tree worm. So, these organisms are in the same species.


Question: Select the organism in the same species as the Indian rock python.

Choices:
- Python molurus
- Lacerta agilis
- Nerodia cyclopion

This organism is an Indian rock python. Its scientific name is Python molurus.

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 Indian rock python's scientific name is Python molurus.
Nerodia cyclopion does not have the same scientific name as an Indian rock python. So, Python molurus and Nerodia cyclopion are not in the same species.
Python molurus has the same scientific name as an Indian rock python. So, these organisms are in the same species.
Lacerta agilis does not have the same scientific name as an Indian rock python. So, Python molurus and Lacerta agilis are not in the same species.


Question: Which statement describes the Eastern Siberian Taiga ecosystem?

Choices:
- It has mostly small plants.
- It has soil that is rich in nutrients.
- It has long, cold winters and short, cool summers.

Figure: East Siberian Taiga.
The Eastern Siberian Taiga is a large forest that covers more than a quarter of Russia. It is home to brown bears, wolves, deer, 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 taiga is a type of ecosystem. Taigas have the following features: long, cold winters and short, cool summers, many evergreen trees, and soil that is poor in nutrients. So, the following statement describes the Eastern Siberian Taiga ecosystem: long, cold winters and short, cool summers, many evergreen trees, and soil that is poor in nutrients. It has long, cold winters and short, cool summers. The following statements do not describe the Eastern Siberian Taiga: long, cold winters and short, cool summers, many evergreen trees, and soil that is poor in nutrients. It has mostly small plants. It has soil that is rich in nutrients.


Question: Identify the question that Heather and Tanner's experiment can best answer.

Choices:
- Does Heather's snowboard slide down a hill in less time when it has a layer of wax or when it does not have a layer of wax?
- Does Heather's snowboard slide down a hill in less time when it has a thin layer of wax or a thick layer of wax?

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

Heather applied a thin layer of wax to the underside of her snowboard and rode the board straight down a hill. Then, she removed the wax and rode the snowboard straight down the hill again. She repeated the rides four more times, alternating whether she rode with a thin layer of wax on the board or not. Her friend Tanner timed each ride. Heather and Tanner calculated the average time it took to slide straight down the hill on the snowboard with wax compared to the average time on the snowboard without wax.
Figure: snowboarding down a hill.

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 two objects have in common?

Choices:
- rough
- stretchy

natural science

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

Solution:
Look at each object.
For each object, decide if it has that property.
A rough object feels scratchy when you touch it. Both objects are rough.
A stretchy object gets longer when you pull on it. Neither of the objects are stretchy.
The property that both objects have in common is rough.


Question: Which trait did this aurochs have? Select the trait you can observe on the fossil.

Choices:
- four legs
- a striped body

This picture shows a fossil of an animal called an aurochs.
The aurochs was hunted by humans and went extinct around 1627. The oldest aurochs fossils are about 2,000,000 years old.

natural science

The way an organism looks or acts is called a trait. Scientists use fossils to learn more about the traits of ancient organisms.
Fossils can preserve the remains of body parts and activities. A fossil of a body part, such as a tail or a wing, can tell you what an organism looked like. A fossil of an organism's activities, such as a burrow or a footprint, can tell you about the organism's behavior.
Here are three examples of fossils and the traits that you can observe from them:
This is a fossil of an animal. This fossil tells you that the animal had a spiral-shaped shell.
This is a fossil of a plant. This fossil tells you that the plant had small leaves arranged in a branched pattern.
This is a fossil of an animal's footprint. This fossil tells you that the animal could walk on land.
An organism's fossil may not show all of the organism's traits. This is because most body parts are destroyed during fossil formation. When an organism's body turns into a fossil, only a few body parts are usually preserved.


Question: Select the reptile below.

Choices:
- sea otter
- tortoise

Reptiles have scaly, waterproof skin. Most reptiles live on land. A box turtle is an example of a reptile.

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 tortoise is a reptile. It has scaly, waterproof skin.
A tortoise's shell protects it from predators. When a tortoise feels threatened, it can pull its head and legs inside its shell.
A sea otter is a mammal. It has fur and feeds its young milk.
Sea otters have very thick fur. Their fur keeps them warm in cold water.


Question: What type of rock is scoria?

Choices:
- igneous
- metamorphic
- sedimentary

This is a piece of scoria. Scoria is usually formed near volcanoes. It comes from melted rock that is rich in iron and magnesium.
Do you see the hollow gaps in this rock? The gaps come from air and water bubbles that became trapped while the melted rock was cooling.

natural science

Classify rocks as igneous, sedimentary, or metamorphic

Igneous rock is formed when melted rock cools and hardens into solid rock. This type of change can occur at Earth's surface or below it.
Sedimentary rock is formed when layers of sediment are pressed together, or compacted, to make rock. This type of change occurs below Earth's surface.
Metamorphic rock is formed when a rock is changed by very high temperature and pressure. This type of change often occurs deep below Earth's surface. Over time, the old rock becomes a new rock with different properties.

Solution:
Scoria is an igneous rock. Like other igneous rocks, it forms when melted rock cools and hardens.
Melted rock at the earth's surface is called lava. Scoria forms from a type of lava that is rich in iron and magnesium. As the lava erupts from a volcano, it can trap small bubbles of air or water. When the lava becomes solid, the bubbles leave behind gaps in the rock.


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

Choices:
- North America
- Africa
- South America

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 Africa. It does not intersect North America or South America.


Question: Select the amphibian below.

Choices:
- common toad
- catfish

Amphibians have moist skin and begin their lives in water. An American bullfrog 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 common toad is an amphibian. It has moist skin and begins its life in water.
A catfish is a fish. It lives underwater. It has fins, not limbs.


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

Choices:
- stretchy
- rough
- bouncy

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 rough object feels scratchy when you touch it. All three objects are rough.
A stretchy object gets longer when you pull on it. The rock and the tree bark are not stretchy.
A bouncy object will bounce back from the floor if you drop it. The tree bark and the velcro are not bouncy.
The property that all three objects have in common is rough.


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

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

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: Which country is highlighted?

Choices:
- Kiribati
- Tuvalu
- Tonga
- the Marshall Islands

social science

Identify and select countries of Oceania

Solution: This country is Tuvalu.


Question: What is the capital of Ohio?

Choices:
- Cleveland
- Columbus
- Frankfort
- Jefferson City

social science

Solution: Columbus is the capital of Ohio.


Question: Which of these cities is marked on the map?

Choices:
- Nashville
- Houston
- Charlotte
- New Orleans

social science

Solution: The city is Houston, Texas. Nashville, New Orleans, and Charlotte are marked with gray circles on the map below.


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: Will these magnets attract or repel each other?

Choices:
- repel
- attract

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: north and south.
Here are some examples of magnets. The north pole of each magnet is labeled N, and the south pole is labeled S.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.

Solution:
To predict if these magnets will attract or repel, look at which poles are closest to each other.
The north pole of one magnet is closest to the south pole of the other magnet. Opposite poles attract. So, these magnets will attract each other.


Question: What is the capital of North Carolina?

Choices:
- Saint Paul
- Fargo
- Raleigh
- Charlotte

social science

Identify state capitals of the Southeast

Solution: Raleigh is the capital of North Carolina.


Question: Which statement is true about the average monthly precipitation in Nairobi?

Choices:
- Nairobi gets about the same amount of precipitation each month.
- More precipitation falls in April than in August.
- February is the wettest month of the year.

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 Nairobi, look at the graph.
Choice "Feb" is incorrect.
Choice "Apr" is incorrect.
Choice "Aug" is incorrect.
Choice "More precipitation falls in April than in August." is incorrect.
April has a higher average monthly precipitation than August.
Choice "Nairobi gets about the same amount of precipitation each month." is incorrect.
On average, less precipitation falls between June and October than between November and May.
Choice "February is the wettest month of the year." is incorrect.
The wettest month is the one with the highest average monthly precipitation. April, not February, has the highest average precipitation.


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

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

The diagram below is a model of two solutions. Each purple 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 purple particles represent the solute. To figure out which solution has a higher concentration of purple particles, look at both the number of purple particles and the volume of the solvent in each container.
Use the concentration formula to find the number of purple particles per milliliter.
Solution A has more purple particles per milliliter. So, Solution A has a higher concentration of purple particles.


Question: Which month has the lowest average precipitation in London?

Choices:
- July
- November
- February

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 London, look at the graph.
Choice "Feb" is incorrect.
Choice "Jul" is incorrect.
Choice "Nov" is incorrect.
July has an average monthly precipitation of about 45 millimeters. This is lower than in any other month. So, July has the lowest average precipitation.


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

Choices:
- Do steel nails take fewer days to rust in water compared to vinegar?
- Do steel nails rust in fewer days when submerged in a large volume of liquid compared to a small volume?

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

Zachary put one two-inch steel nail into each of six test tubes. He added water to three of the test tubes and vinegar to the other three. In each test tube, he completely covered the nail with the same volume of liquid. Zachary checked the nails for rust at the same time every day. He recorded how many days it took each nail to become completely covered in rust. Then, he compared the number of days it took nails to rust in water to the number of days it took nails to rust in vinegar.
Figure: a new steel nail on a pile of rusty nails.

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:
- Kiribati
- Nauru
- the Marshall Islands
- Solomon Islands

social science

Identify and select countries of Oceania

Solution:
This country is the Marshall Islands.
Does the Marshall Islands have any territorial disputes?
The Marshall Islands claims to own Wake Island, which is a disputed territory. In other words, multiple countries or groups claim that the area rightfully belongs to them.
The United States claimed Wake Island in 1899 and has controlled it since then. But the Marshall Islands considers the island part of its territory. It says that its people have traveled to the island to gather food and resources for many years. Today, the island is mainly used by the U.S. Air Force.


Question: Which of these states is farthest east?

Choices:
- Louisiana
- Ohio
- Maine
- Tennessee

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. Maine is farthest east.


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

Choices:
- sticky
- salty
- 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.
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.
Potato chips have a salty taste. All three objects are salty.
A colorful object has one or more bright colors. None of the objects are colorful.
A sticky object can attach or stick to other things. None of the objects are sticky.
The property that all three objects have in common is salty.


Question: Which animal is also adapted to be camouflaged in a sandy desert?

Choices:
- horned viper
- blue poison dart frog

Bearded dragons are lizards that live in the deserts of Australia. The  is adapted to be camouflaged in a sandy desert.
Figure: bearded dragon.

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 bearded dragon.
The bearded dragon has a sand-colored body. It is adapted to be camouflaged in a sandy desert. The word camouflage means to blend in.
Now look at each animal. Figure out which animal has a similar adaptation.
The horned viper has sand-colored scales covering its body. It is adapted to be camouflaged in a sandy desert.
The blue poison dart frog has brightly colored skin. It is not adapted to be camouflaged in a sandy desert.


Question: What can Vivian and Jamal trade to each get what they want?

Choices:
- Vivian can trade her tomatoes for Jamal's broccoli.
- Jamal can trade his broccoli for Vivian's oranges.
- Vivian can trade her tomatoes for Jamal's carrots.
- Jamal can trade his almonds for Vivian'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.
Vivian and Jamal open their lunch boxes in the school cafeteria. Neither Vivian nor Jamal 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.
Vivian's lunch Jamal's lunch

social science

Solution:
Look at the table and images.
Vivian wants broccoli. Jamal 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 continent is highlighted?

Choices:
- Antarctica
- North America
- Asia
- Europe

social science

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

Solution: This continent is Europe.


Question: What is the capital of Nevada?

Choices:
- Las Vegas
- Reno
- Cheyenne
- Carson City

social science

Solution: Carson City is the capital of Nevada.


Question: Which of these states is farthest south?

Choices:
- Texas
- Maryland
- Michigan
- Rhode Island

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. Texas is farthest south.


Question: Is a crown a solid or a liquid?

Choices:
- a liquid
- a solid

natural science

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

Solution:
A crown is a solid. A solid has a size and shape of its own.
If you put a crown on your head, the crown will keep its shape.


Question: Select the organism in the same genus as the gray tree frog.

Choices:
- Hyla cinerea
- Atelopus zeteki
- Hemidactylus turcicus

This organism is a gray tree frog. Its scientific name is Hyla versicolor.

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 gray tree frog's scientific name is Hyla versicolor. The first word of its scientific name is Hyla.
Atelopus zeteki is in the genus Atelopus. The first word of its scientific name is Atelopus. So, Atelopus zeteki and Hyla versicolor are not in the same genus.
Hemidactylus turcicus is in the genus Hemidactylus. The first word of its scientific name is Hemidactylus. So, Hemidactylus turcicus and Hyla versicolor are not in the same genus.
Hyla cinerea is in the genus Hyla. The first word of its scientific name is Hyla. So, Hyla cinerea and Hyla versicolor are in the same genus.


Question: Which animal's mouth is also adapted to eat plant matter?

Choices:
- spotted deer
- Nile crocodile

Kudus are herbivores, or plant eaters. They eat leaves and shoots. The 's mouth is adapted to grind up and eat plant matter.
Figure: kudu.

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 kudu.
The kudu has long jaws and flat teeth. Its mouth is adapted to eat plant matter. The long jaws can help the kudu reach leaves and shoots. The flat teeth can help it cut and grind up the food into soft pieces it can swallow.
Now look at each animal. Figure out which animal has a similar adaptation.
The spotted deer has long jaws and flat teeth. Its mouth is adapted to eat plant matter.
The Nile crocodile has a large mouth and sharp teeth. Its mouth is not adapted to eat plant matter. The Nile crocodile uses its mouth to eat other animals.


Question: What can Janice and Abdul trade to each get what they want?

Choices:
- Abdul can trade his almonds for Janice's tomatoes.
- Janice can trade her tomatoes for Abdul's carrots.
- Janice can trade her tomatoes for Abdul's broccoli.
- Abdul can trade his broccoli for Janice'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.
Janice and Abdul open their lunch boxes in the school cafeteria. Neither Janice nor Abdul 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.
Janice's lunch Abdul's lunch

social science

Solution:
Look at the table and images.
Janice wants broccoli. Abdul 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 ocean is highlighted?

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

social science

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

Solution:
This is the Southern Ocean.
The Southern Ocean reaches from the shores of Antarctica to 60° South latitude.


Question: Which term matches the picture?

Choices:
- echinoderm
- cnidarian

Read the text.
Invertebrates make up the majority of Earth's living things, but there are many different groups, or phyla, of invertebrates. Jellyfish and sea anemone, for example, are both part of the phylum Cnidaria. Cnidaria comes from a Greek word that means "nettle," a stinging type of plant. Cnidarians are known for the tentacles that surround their mouths, which they use to sting and capture prey. All species that belong in the Cnidaria phyla live exclusively in the ocean.
Another phylum of invertebrates found only in oceans is the Echinodermata, a term that comes from Greek words meaning "spiny" and "skin." Echinoderms, members of this phylum, have stiff bodies and often have stiff, sharp spines covering their skins. Unlike a cnidarian's wavy tentacles, these spines are used for protection, not to capture prey.

language science

Determine the meaning of domain-specific words with pictures

Solution: An echinoderm is a type of sea invertebrate that usually has sharp or spiky skin. A sea urchin is a type of echinoderm.


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

Choices:
- Do steel nails rust in fewer days when submerged in a large volume of liquid compared to a small volume?
- Do steel nails take fewer days to rust in water compared to vinegar?

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

Logan put one two-inch steel nail into each of six test tubes. He added water to three of the test tubes and vinegar to the other three. In each test tube, he completely covered the nail with the same volume of liquid. Logan checked the nails for rust at the same time every day. He recorded how many days it took each nail to become completely covered in rust. Then, he compared the number of days it took nails to rust in water to the number of days it took nails to rust in vinegar.
Figure: a new steel nail on a pile of rusty nails.

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: 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: Which property matches this object?

Choices:
- transparent
- smooth

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 smooth object is not scratchy or rough. The silk tie is smooth.
You can see clearly through a transparent object. The silk tie is not transparent.


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 1.
- The magnitude of the magnetic force is greater in Pair 2.
- 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, 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 greater when there is a smaller distance between the magnets.

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


Question: Which ocean is highlighted?

Choices:
- the Indian Ocean
- the Arctic Ocean
- the Pacific Ocean
- the Southern Ocean

social science

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


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

Choices:
- soft
- fragile
- scratchy

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 scratchy object is rough and itchy against your skin. None of the objects are scratchy.
A soft object changes shape when pressed or squeezed. None of the objects are soft.
A fragile object will break into pieces if you drop it. All three objects are fragile.
The property that all three objects have in common is fragile.


Question: What is the expected ratio of offspring with black fur to offspring with brown fur? Choose the most likely ratio.

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

In a group of rabbits, some individuals have black fur and others have brown fur. In this group, the gene for the fur color trait has two alleles. The allele for brown fur (f) is recessive to the allele for black fur (F).
This Punnett square shows a cross between two rabbits.

natural science

Use Punnett squares to calculate ratios of offspring types

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

Solution:
To determine how many boxes in the Punnett square represent offspring with black fur or brown fur, consider whether each phenotype is the dominant or recessive allele's version of the fur color trait. The question tells you that the f allele, which is for brown fur, is recessive to the F allele, which is for black fur.
Black fur is the dominant allele's version of the fur color trait. A rabbit with the dominant version of the fur color trait must have at least one dominant allele for the fur color gene. So, offspring with black fur must have the genotype FF or Ff.
There are 3 boxes in the Punnett square with the genotype FF or Ff. These boxes are highlighted below.
Brown fur is the recessive allele's version of the fur color trait. A rabbit with the recessive version of the fur color trait must have only recessive alleles for the fur color gene. So, offspring with brown fur must have the genotype ff.
There is 1 box in the Punnett square with the genotype ff. This box is highlighted below.
So, the expected ratio of offspring with black fur to offspring with brown fur is 3:1. This means that, on average, this cross will produce 3 offspring with black fur for every 1 offspring with brown fur.


Question: Which state is highlighted?

Choices:
- Idaho
- Wyoming
- Utah
- California

social science

Solution: This state is Idaho.


Question: Select the organism in the same species as the blue jay.

Choices:
- Cyanocitta cristata
- Larus michahellis
- Goura victoria

This organism is a blue jay. Its scientific name is Cyanocitta cristata.

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 blue jay's scientific name is Cyanocitta cristata.
Larus michahellis does not have the same scientific name as a blue jay. So, Cyanocitta cristata and Larus michahellis are not in the same species.
Goura victoria does not have the same scientific name as a blue jay. So, Cyanocitta cristata and Goura victoria are not in the same species.
Cyanocitta cristata has the same scientific name as a blue jay. So, these organisms are in the same species.


Question: What is the capital of Maine?

Choices:
- Portland
- Burlington
- Augusta
- Madison

social science

Identify state capitals of the Northeast

Solution: Augusta is the capital of Maine.


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

Choices:
- Neofelis nebulosa
- Cyanea capillata
- Strix varia

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. The first word of its scientific name is Strix.
Cyanea capillata is in the genus Cyanea. The first word of its scientific name is Cyanea. So, Cyanea capillata and Strix nebulosa are not in the same genus.
Neofelis nebulosa and Strix nebulosa are not in the same genus.
These organisms are not in the same genus, but part of their scientific names is the same. Neofelis nebulosa and Strix nebulosa have the same species name within their genus, nebulosa. But the first words of their scientific names are different. Neofelis nebulosa is in the genus Neofelis, and Strix nebulosa is in the genus Strix.
Strix varia is in the genus Strix. The first word of its scientific name is Strix. So, Strix varia and Strix nebulosa are in the same genus.


Question: According to the text, what evidence of a volcanic eruption did the captain observe?

Choices:
- He heard a report on the radio warning about a volcanic eruption.
- He saw a nearby boat that was on fire.
- He smelled sulfur and saw pieces of molten rock shooting out of the water.

Before sunrise on November 14, 1963, the crew of the fishing boat Isleifur II had just finished putting their fishing lines in the ocean off the southern coast of Iceland. As the crew waited to have breakfast, a strong smell of sulfur drifted over the boat. At first, crew members thought that the cook had burned the eggs or that something was wrong with the boat's engine. But when the sun started to rise, the crew saw black smoke billowing from the water a few kilometers away.
The captain of the Isleifur II first thought the smoke was coming from a boat that was on fire, so he sailed closer to try to help. But as the Isleifur II approached the column of smoke, the captain and crew saw glowing pieces of molten rock shooting up out of the water. The captain realized this was not a burning boat. It was a volcano erupting under the water!
Figure: the erupting undersea volcano seen by the sailors on the Isleifur II.

natural science

Investigate primary succession on a volcanic island


Question: What is the capital of Florida?

Choices:
- Denver
- Tallahassee
- Tampa
- Orlando

social science

Identify state capitals of the Southeast

Solution: Tallahassee is the capital of Florida.


Question: What can Bill and Anita trade to each get what they want?

Choices:
- Anita can trade her almonds for Bill's tomatoes.
- Anita can trade her broccoli for Bill's oranges.
- Bill can trade his tomatoes for Anita's broccoli.
- Bill can trade his tomatoes for Anita'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.
Bill and Anita open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Bill wanted broccoli in his lunch and Anita was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.

social science

Solution:
Bill wanted broccoli in his lunch and Anita was hoping for tomatoes. Look at the labeled part of the images.
Bill has tomatoes. Anita 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:
- blue
- sticky
- 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. The kiwi and the stuffed dice are not blue.
A fuzzy object is covered in soft hair. All three objects are fuzzy.
A sticky object can attach or stick to other things. The socks and the stuffed dice are not sticky.
The property that all three objects have in common is fuzzy.


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

Choices:
- Do steel nails take fewer days to rust in water compared to vinegar?
- Do steel nails rust in fewer days when submerged in a large volume of liquid compared to a small volume?

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

Carter put one two-inch steel nail into each of six test tubes. He added water to three of the test tubes and vinegar to the other three. In each test tube, he completely covered the nail with the same volume of liquid. Carter checked the nails for rust at the same time every day. He recorded how many days it took each nail to become completely covered in rust. Then, he compared the number of days it took nails to rust in water to the number of days it took nails to rust in vinegar.
Figure: a new steel nail on a pile of rusty nails.

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: What is the capital of Colorado?

Choices:
- Nampa
- Denver
- Dover
- Phoenix

social science

Solution: Denver is the capital of Colorado.


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

Choices:
- The magnetic force is stronger in Pair 1.
- The magnetic force is stronger in Pair 2.
- The strength 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 stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other.
You can change the strength of a magnetic force between two magnets by changing the distance between them. The magnetic force is stronger when the magnets are closer together.

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


Question: Based on the Venn diagram, which statement is true of Leonardo da Vinci?

Choices:
- He was from Florence.
- He created David.

language science

A graphic organizer is a chart or picture that shows how ideas, facts, or topics are related to one another.
When you read, look for graphic organizers included in the text. You can use these images to find key information. You can also create your own graphic organizers with information that you've read. Doing this can help you think about the ideas in the text and easily review them.
When you write, you can use graphic organizers to organize your thoughts and plan your writing.

Solution:
In a Venn diagram, each circle shows information that is true for a particular topic. In any area where circles overlap, the information is true for all of the overlapping topics. This Venn diagram compares two famous Renaissance artists.
The detail from Florence appears in the Leonardo da Vinci circle. This tells you that he was from Florence.


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

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

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 of the following could Jennifer and Scarlett's test show?

Choices:
- if a new batch of concrete was firm enough to use
- if the concrete from each batch took the same amount of time to dry

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design.
The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below.

Jennifer and Scarlett were making batches of concrete for a construction project. To make the concrete, they mixed together dry cement powder, gravel, and water. Then, they checked if each batch was firm enough using a test called a slump test.
They poured some of the fresh concrete into an upside-down metal cone. They left the concrete in the metal cone for 30 seconds. Then, they lifted the cone to see if the concrete stayed in a cone shape or if it collapsed. If the concrete in a batch collapsed, they would know the batch should not be used.
Figure: preparing a concrete slump test.

natural science

Evaluate tests of engineering-design solutions

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


Question: What is the capital of West Virginia?

Choices:
- Charleston
- Baton Rouge
- Portland
- Huntington

social science

Identify state capitals of the Southeast

Solution: Charleston is the capital of West Virginia.


Question: Is a coffee mug a solid, a liquid, or a gas?

Choices:
- a gas
- a liquid
- a solid

natural science

Identify and sort solids, liquids, and gases

Solid, liquid, and gas are states of matter. Matter is anything that takes up space. Matter can come in different states, or forms.
When matter is a solid, it has a definite volume and a definite shape. So, a solid has a size and shape of its own.
Some solids can be easily folded, bent, or broken. A piece of paper is a solid. Also, some solids are very small. A grain of sand is a solid.
When matter is a liquid, it has a definite volume but not a definite shape. So, a liquid has a size of its own, but it does not have a shape of its own. Think about pouring juice from a bottle into a cup. The juice still takes up the same amount of space, but it takes the shape of the bottle.
Some liquids are thicker than others. Honey and milk are both liquids. But pouring honey takes more time than pouring milk.
When matter is a gas, it does not have a definite volume or a definite shape. A gas expands, or gets bigger, until it completely fills a space. A gas can also get smaller if it is squeezed into a smaller space.
Many gases are invisible. The oxygen you breathe is a gas. The helium in a balloon is also a gas.

Solution:
A coffee mug is a solid. A solid has a size and shape of its own.
When you pour coffee into a coffee mug, the mug keeps its shape. If you drop a coffee mug, it may break into pieces. But each piece will still have a size and shape of its own.


Question: Which i in column 3?

Choices:
- the school
- the park
- the pond
- the gas station

social science

A grid is made up of lines of squares. They are organized in rows and columns. A grid can help you use a map.
A row is a line of squares that goes from side to side. Rows are marked with letters.
A column is a line of squares that goes up and down. Columns are marked with numbers.

Solution: The school is in column 3.


Question: Which continent is highlighted?

Choices:
- Africa
- South America
- Europe
- Australia

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 Europe.


Question: Based on the painting, which was true about ironclads?

Choices:
- They were powered by oars.
- They didn't have weapons.
- They were made of metal.
- They used sails.

The Union and Confederacy built many new ships during the Civil War. This is a painting of the first battle between two ironclads, the CSS Virginia and the USS Monitor. Use it to answer the question below.

social science

The Civil War: war tactics and the home front

Solution: Notice how the two ironclads have smooth, reflective surfaces. Ironclads gained their name because they were made of metal. Iron is a type of metal. Before the Civil War, naval ships were made of wood. Metal ships such as ironclads were stronger than ships made of wood.


Question: What is the capital of Vermont?

Choices:
- Burlington
- Montpelier
- Annapolis
- Philadelphia

social science

Identify state capitals of the Northeast

Solution: Montpelier is the capital of Vermont.


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

Choices:
- The magnetic force is stronger in Pair 1.
- The strength of the magnetic force is the same in both pairs.
- 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: What is the direction of this push?

Choices:
- away from the baseball bat
- toward the baseball bat

A baseball player hits the ball with his bat. His bat pushes the ball into the outfield.

natural science

One object can make another object move with a push or a pull.
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: Hitting a baseball with a bat is a type of push. The baseball player hits the ball away from his bat. The ball flies into the field. The direction of the push is away from the baseball bat.


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

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

The diagram below is a model of two solutions. Each pink 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 pink particles represent the solute. To figure out which solution has a higher concentration of pink particles, look at both the number of pink particles and the volume of the solvent in each container.
Use the concentration formula to find the number of pink particles per milliliter.
Solution A has more pink particles per milliliter. So, Solution A has a higher concentration of pink particles.


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

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

The diagram below is a model of two solutions. Each green 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 green particles represent the solute. To figure out which solution has a higher concentration of green particles, look at both the number of green particles and the volume of the solvent in each container.
Use the concentration formula to find the number of green particles per milliliter.
Solution B has more green particles per milliliter. So, Solution B has a higher concentration of green particles.


Question: Which of the following could Carter's test show?

Choices:
- the amount of sunlight the roof would get throughout the year
- how many solar panels could fit on each side of the roof
- which side of the roof got more sun over one day

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design.
The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below.

Carter was installing solar panels on the roof of a client's house. The panels had to provide enough electricity to power the house year-round. Carter needed to decide how many panels to install and which side of the roof to install them on. If he put the panels on the side that got the most sun, then he could use fewer panels, and the client would save money. Carter installed sunlight sensors on both sides of the roof. Then, he measured the amount of sunlight the sensors on each side of the roof recorded over one sunny summer day.
Figure: installing solar panels on a roof.

natural science

Evaluate tests of engineering-design solutions

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


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.

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.

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.
Both magnet sizes and distance affect the magnitude of the magnetic force. The sizes of the magnets in Pair 1 are the same as in Pair 2. The distance between the magnets is also the same.
So, the magnitude of the magnetic force is the same in both pairs.