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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

5. Test

California Grade 8 CAST Science Practice Questions

A 10-question California Grade 8 CAST Science practice set on environmental systems and data, 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 drought reduces plant growth in a grassland. What is a likely effect on herbivores?

Please select an answer first.

Correct answer: A

The correct answer is Their population may decrease because less food is available..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Reduced plant growth can limit food for herbivores and affect their population.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Reduced plant growth can limit food for herbivores and affect their population.

2. QuestionMultiple choice

A city replaces trees with pavement and later records higher summer temperatures. What process may explain the result?

Please select an answer first.

Correct answer: B

The correct answer is Pavement absorbs and re-radiates more heat than shaded vegetated surfaces..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Surface properties and loss of shade can change how energy is absorbed and released.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Surface properties and loss of shade can change how energy is absorbed and released.

3. QuestionMultiple choice

Which evidence best supports the claim that a lake is becoming more polluted?

Please select an answer first.

Correct answer: C

The correct answer is Long-term measurements show increasing concentrations of a contaminant..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Repeated chemical measurements provide direct evidence of a changing pollutant concentration.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Repeated chemical measurements provide direct evidence of a changing pollutant concentration.

4. QuestionMultiple choice

Why can an invasive species reduce biodiversity?

Please select an answer first.

Correct answer: D

The correct answer is It may compete with native species for food, space, or other 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: Invasive species can change resource competition and reduce native populations.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Invasive species can change resource competition and reduce native populations.

5. QuestionMultiple choice

A graph shows that recycling increases while landfill waste decreases after a new program. What conclusion is supported?

Please select an answer first.

Correct answer: A

The correct answer is The program is associated with a reduction in landfill waste..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: The paired trends are consistent with the program reducing the amount sent to landfills.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

The paired trends are consistent with the program reducing the amount sent to landfills.

6. QuestionMultiple choice

Which practice helps maintain groundwater supplies?

Please select an answer first.

Correct answer: B

The correct answer is Using water at a rate that does not exceed recharge..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Sustainable use keeps withdrawals near the rate at which groundwater is replenished.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Sustainable use keeps withdrawals near the rate at which groundwater is replenished.

7. QuestionMultiple choice

A population graph rises quickly, then decreases after food becomes scarce. What does this show?

Please select an answer first.

Correct answer: C

The correct answer is Resource limits can cause a population to decline..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Limited resources can reduce survival and reproduction after a period of growth.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Limited resources can reduce survival and reproduction after a period of growth.

8. QuestionMultiple choice

A researcher compares two wetlands, one with many plant species and one with few. Which measurement could show greater ecosystem stability?

Please select an answer first.

Correct answer: D

The correct answer is The diverse wetland maintains water quality after a disturbance more consistently..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Stability can be assessed by how well systems maintain function after change.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Stability can be assessed by how well systems maintain function after change.

9. QuestionMultiple choice

Which change would most reduce carbon dioxide released by a school?

Please select an answer first.

Correct answer: A

The correct answer is Using less fossil-fuel energy through efficiency and renewable power..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Efficiency and renewable energy can reduce fossil-fuel combustion and associated emissions.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Efficiency and renewable energy can reduce fossil-fuel combustion and associated emissions.

10. QuestionMultiple choice

Why should environmental data be collected over multiple seasons?

Please select an answer first.

Correct answer: B

The correct answer is Seasonal variation can be separated from longer-term patterns..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, engineering, or systems science.
  2. Use the evidence: Multiple seasons help distinguish normal seasonal cycles from broader changes.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Multiple seasons help distinguish normal seasonal cycles from broader changes.

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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.