CAST practice #2

Use the graphs and the partial food web to predict the changes in the sea urchin population as the kelp pupulation INCREASES. What will happen to the sea urchin population?

• Sea urchin population increases

• Sea urchin population decreases

• Sea urchin population remains steady

Answer explanation

As the kelp population increases, it provides more food and habitat for sea urchin predators, leading to a decrease in the sea urchin population. Therefore, the correct answer is that the sea urchin population decreases.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-3

NGSS.MS-LS2-4

Use the graphs and the partial food web to predict the changes in the kelp population as the kelp pupulation INCREASES. What will happen to the kelp population?

• Kelp population increases

• Kelp population decreases

• Kelp population remains steady

Answer explanation

As the kelp population increases, it may lead to overgrazing by herbivores, resulting in a decrease in kelp. Thus, the correct prediction is that the kelp population decreases.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-3

NGSS.MS-LS2-4

A student conducts 5 trials to investigate factors affecting the formation of impact craters. The student drops a marble into a box with fine powder. Analyze the results in the graph pictured. Because the mass is 40g in each trial, mass is a...

• constant

• control

• dependent variable

• independent variable

Answer explanation

In this experiment, the mass of the marble is kept constant at 40g across all trials. This means it does not change and is not being tested as a variable, making it a constant in the investigation.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-1

A student conducts 5 trials to investigate factors affecting the formation of impact craters. The student drops a marble into a box with fine powder to measure the depth. Analyze the results in the graph pictured. Depth is the

• constant

• control

• dependent variable

• independent variable

Answer explanation

In this experiment, the depth of the crater formed by the marble is measured as a response to the impact. Therefore, depth is the dependent variable, as it depends on the conditions of the trials.

A student conducts 5 trials to investigate factors affecting the formation of impact craters. The student drops a marble into a box with fine powder at different speeds to measure the depth. Analyze the results in the graph pictured. Speed is the

• constant

• control

• dependent variable

• independent variable

Answer explanation

In this experiment, the speed at which the marble is dropped is manipulated to observe its effect on crater depth. Therefore, speed is the independent variable, as it is the factor being changed to see how it influences the outcome.

Tags

NGSS.MS-PS3-1

A student conducts 5 trials to investigate factors affecting the formation of impact craters and here are the results. What is true about the results of the experiment?

• As the speed of the marble increases, the depth of the crater increases

• As the speed of the marble increases, the depth of the crater decreases

• As the speed of the marble increases, the depth of the crater stays the same

Answer explanation

The results indicate that as the speed of the marble increases, it impacts with greater force, leading to a deeper crater. Therefore, the correct statement is that as the speed of the marble increases, the depth of the crater increases.

Tags

NGSS.MS-PS3-1

A student conducts 5 trials to investigate factors affecting the formation of impact craters and here are the results. Which statement BEST describes the results of the investigation?

• The kinetic energy of the marble just before impact is proportional to the depth of the crater it forms

• The kinetic energy of the marble just before impact is proportional to the mass of the marble

• The depth of the crater is proportional to the mass of the marble

• The depth of the crater is proportional to the mass of the marble

Answer explanation

The correct statement indicates that the kinetic energy of the marble affects the crater's depth. As the marble's kinetic energy increases, it creates a deeper crater, showing a direct relationship between energy and crater depth.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

Read the question in the photo. Select a moon location in the model that supports the explanation that the New Moon phase explains why the disk becomes a ring.

• 1

• 2

• 3

• 4

Answer explanation

Choice 2 shows the moon in the New Moon phase, where it is positioned between the Earth and the Sun. This alignment causes the illuminated part of the moon to be hidden, resulting in the appearance of a ring around the dark disk.

Tags

NGSS.MS-ESS1-1

A student reviews the model shown and says that, based on the model, a solar eclipse should happen every time there is a new moon. However, solar eclipses occur less often than New Moons. Which feature of the model should be revised to best explain why solar eclipses do not happen every month?

• The model should show that the shape of the Earth's orbit around the Sun is an ellipse.

• The model should show that the shape of the Moon's orbit around the Earth is an ellipse.

• The model should show that Earth's equator is inclined relative to the plane of Earth's orbit around the Sun.

• The model should show that the plane of the Moon's orbit around the Earth is inclined relative to the plane of Earth's orbit around the Sun.

Answer explanation

The model should show that the plane of the Moon's orbit around the Earth is inclined relative to the plane of Earth's orbit around the Sun. This inclination prevents solar eclipses from occurring every new moon.

Tags

NGSS.MS-ESS1-1

Leah is learning to use properties of substances to identify a chemical reaction. She conducts two trials. In the first trial, she pours silicon dioxide (SiO2) into water (H2O). For the second trial, she pours silver nitrate (AgNO3) solution into a test tube with a solution of potassium chloride (KCl). Look at the diagram. In which trial did a chemical reaction occur?

• Trial 1

• Trial 2

• Both trial 1 and trial 2

• No chemical reaction happened in either

Answer explanation

In Trial 1, silicon dioxide does not react with water, so no chemical reaction occurs. In Trial 2, silver nitrate and potassium chloride react to form a precipitate of silver chloride, indicating a chemical reaction.

Tags

NGSS.MS-PS1-2