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California CAST · Grade 8 · Science

California Grade 8 CAST Science Practice Test

Build Grade 8 California CAST Science readiness with five focused 10-question practice sets covering life science, physical science, Earth and space science, engineering, and environmental data.

Grade 8 CAST Science practice sets

This California Grade 8 CAST Science Practice Test page provides five short practice sets with 10 original multiple-choice questions each. The sets support supplemental review across life science systems, heredity, physical science, Earth and space processes, engineering practices, environmental systems, and data analysis.

Science skills covered

  • Cell transport, cell division, heredity, natural selection, genes and proteins, ecosystems, reproduction, mutations, common ancestry, and adaptation
  • Conservation of matter, gas particles, motion, energy, thermal transfer, circuits, physical and chemical change, forces, friction, and waves
  • Earthquakes, plate boundaries, rocks, ocean currents, Moon motion, paleoclimate, water cycle, seasons, and glaciers
  • Controlled variables, models and limitations, engineering trade-offs, reaction data, reliable measurement, prototypes, and scientific explanations
  • Drought, urban heat, pollution, invasive species, recycling, groundwater, populations, biodiversity, carbon emissions, and seasonal data

How to use this page

Complete one 10-question set at a time. Identify the evidence, describe the mechanism, and review every explanation before moving to the next set.

This is supplemental State Test Practice, State Assessment Practice, and Standardized Test Practice. It does not replace current California Department of Education guidance, official CAST blueprints, accommodations, or testing schedules.

For the broader California assessment hub, visit California State Assessments.

Select a test

5 Tests
1. Test2. Test3. Test4. Test5. Test

1. Test

California Grade 8 CAST Science Practice Questions

A 10-question California Grade 8 CAST Science practice set on life science systems and heredity, with answers and explanations.

Read each science task carefully, choose one answer, and review the explanation after responding.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

A cell uses energy to move particles from an area of low concentration to an area of high concentration. Which process is occurring?

Please select an answer first.

Correct answer: A

The correct answer is Active transport.

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Active transport moves substances against a concentration gradient and requires energy.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Active transport moves substances against a concentration gradient and requires energy.

2. QuestionMultiple choice

Why do cells divide during growth and repair?

Please select an answer first.

Correct answer: B

The correct answer is Division produces new cells with genetic material needed for body functions..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Cell division allows organisms to grow and replace damaged cells.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Cell division allows organisms to grow and replace damaged cells.

3. QuestionMultiple choice

A trait appears in some offspring but not in either parent’s visible traits. Which explanation is possible?

Please select an answer first.

Correct answer: C

The correct answer is Both parents carried a recessive allele..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: A recessive trait can appear when an offspring receives a recessive allele from each parent.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

A recessive trait can appear when an offspring receives a recessive allele from each parent.

4. QuestionMultiple choice

A population of insects becomes more resistant to a pesticide over generations. What best explains this change?

Please select an answer first.

Correct answer: D

The correct answer is Resistant insects survive and reproduce, increasing the frequency of resistance..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Natural selection increases inherited traits that improve survival in the environment.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Natural selection increases inherited traits that improve survival in the environment.

5. QuestionMultiple choice

Which statement best describes the relationship between genes and proteins?

Please select an answer first.

Correct answer: A

The correct answer is Genes contain information used to make proteins..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Genes provide instructions that cells use to produce proteins.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Genes provide instructions that cells use to produce proteins.

6. QuestionMultiple choice

In an ecosystem, what is likely to happen if a disease greatly reduces a predator population?

Please select an answer first.

Correct answer: B

The correct answer is The predator’s prey may increase and consume more of their food resources..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Fewer predators can allow prey to increase, changing other relationships in the food web.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Fewer predators can allow prey to increase, changing other relationships in the food web.

7. QuestionMultiple choice

Why can asexual reproduction produce offspring that are genetically similar to the parent?

Please select an answer first.

Correct answer: C

The correct answer is It uses genetic material from one parent without combining two sets of alleles..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Asexual reproduction commonly produces genetically similar offspring from one parent.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Asexual reproduction commonly produces genetically similar offspring from one parent.

8. QuestionMultiple choice

A mutation changes a protein involved in cell communication. What could result?

Please select an answer first.

Correct answer: D

The correct answer is The cell may respond differently to signals..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Changing a protein can alter how cells receive or respond to signals.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Changing a protein can alter how cells receive or respond to signals.

9. QuestionMultiple choice

Which evidence best supports a claim that two species share a common ancestor?

Please select an answer first.

Correct answer: A

The correct answer is They have similar inherited structures and genetic sequences..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Inherited structural and genetic similarities can provide evidence of common ancestry.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Inherited structural and genetic similarities can provide evidence of common ancestry.

10. QuestionMultiple choice

A scientist observes that a population has more individuals with a thick fur trait after several cold winters. What is the best explanation?

Please select an answer first.

Correct answer: B

The correct answer is The trait may improve survival and reproduction in the colder environment..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: If thick fur is heritable and helpful, natural selection can make it more common.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

If thick fur is heritable and helpful, natural selection can make it more common.

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Frequently asked questions about California Grade 8 CAST Science Practice Test

Which Science skills are covered?

The page covers Grade 8 life science, physical science, Earth and space science, engineering practices, environmental systems, and data analysis.

How many questions are included?

There are five practice sets with 10 questions each, for 50 questions in total. Each set can be completed separately.

Are these official CAST questions?

No. These are original supplemental practice questions. Check the latest California Department of Education information for official materials, standards, accommodations, and policies.