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California CAST · High School · Science

California High School CAST Science Practice Test

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

High School CAST Science practice sets

This California High School 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, physical science, Earth and space science, environmental systems, engineering design, data analysis, and scientific reasoning.

Science skills covered

  • Population dynamics, ecosystems, mutations, meiosis, natural selection, photosynthesis, decomposers, speciation, alleles, and homeostasis
  • Particle motion, reaction energy, reaction rates, conservation of atoms, circuits, graphs, gravity, waves, and catalysts
  • Mantle convection, plate tectonics, greenhouse gases, stars, redshift, tides, carbon cycling, ice cores, solar energy, and radioactive dating
  • Food webs, wetlands, eutrophication, fisheries, biodiversity, stormwater, climate feedbacks, conservation, ocean chemistry, and data scales
  • Engineering optimization, repeated trials, extrapolation, controlled variables, model revision, correlation, uncertainty, unexpected results, constraints, and outliers

How to use this page

Complete one 10-question set at a time. Identify the evidence, explain the mechanism, and review every solution 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
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4. Test

California High School CAST Science Practice Questions

A 10-question California High School CAST Science practice set on environmental systems and climate, 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

What is a likely consequence of removing a top predator from a food web?

Please select an answer first.

Correct answer: A

The correct answer is A prey population may increase and alter lower trophic levels..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Removing a top predator can produce a trophic cascade through the food web.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Removing a top predator can produce a trophic cascade through the food web.

2. QuestionMultiple choice

Why can wetlands reduce flooding after heavy rain?

Please select an answer first.

Correct answer: B

The correct answer is Wetland soils and vegetation store and slow moving water..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Wetlands can hold water and reduce the speed at which it reaches downstream areas.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Wetlands can hold water and reduce the speed at which it reaches downstream areas.

3. QuestionMultiple choice

A lake receives excess fertilizer and develops a large algal bloom. What may happen next?

Please select an answer first.

Correct answer: C

The correct answer is Decomposition can reduce dissolved oxygen and harm aquatic organisms..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Algal growth followed by decomposition can consume dissolved oxygen.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Algal growth followed by decomposition can consume dissolved oxygen.

4. QuestionMultiple choice

Which practice best supports sustainable fisheries?

Please select an answer first.

Correct answer: D

The correct answer is Harvesting at a rate that allows the population to reproduce and recover..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Sustainable harvest keeps removals within the population’s ability to replenish itself.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Sustainable harvest keeps removals within the population’s ability to replenish itself.

5. QuestionMultiple choice

Why can biodiversity make an ecosystem more resilient to disturbance?

Please select an answer first.

Correct answer: A

The correct answer is Different species may provide overlapping functions and respond differently to change..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Functional variety can help ecosystems maintain processes when some species are affected.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Functional variety can help ecosystems maintain processes when some species are affected.

6. QuestionMultiple choice

What is one likely result of increased urbanization without stormwater planning?

Please select an answer first.

Correct answer: B

The correct answer is More impervious surfaces can increase runoff and reduce groundwater recharge..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Impervious surfaces prevent infiltration and can increase rapid runoff.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Impervious surfaces prevent infiltration and can increase rapid runoff.

7. QuestionMultiple choice

How can a feedback loop amplify climate warming?

Please select an answer first.

Correct answer: C

The correct answer is Warming melts reflective ice, allowing darker surfaces to absorb more energy..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Reduced albedo can increase absorbed energy and reinforce warming.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Reduced albedo can increase absorbed energy and reinforce warming.

8. QuestionMultiple choice

Which evidence would best evaluate whether a conservation program increased a species population?

Please select an answer first.

Correct answer: D

The correct answer is Population counts collected with the same method before and after the program..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Comparable repeated surveys allow population changes to be evaluated.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Comparable repeated surveys allow population changes to be evaluated.

9. QuestionMultiple choice

Why can burning fossil fuels affect ocean chemistry?

Please select an answer first.

Correct answer: A

The correct answer is More atmospheric carbon dioxide can dissolve in seawater and form carbonic acid..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Dissolved carbon dioxide participates in reactions that can lower ocean pH.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Dissolved carbon dioxide participates in reactions that can lower ocean pH.

10. QuestionMultiple choice

What is the best reason to combine local and global environmental data?

Please select an answer first.

Correct answer: B

The correct answer is Different scales reveal how local observations relate to broader patterns..

  1. Identify the science idea: Determine whether the task focuses on life, physical, Earth and space, environmental, or engineering science.
  2. Use the evidence: Multiple scales help scientists connect site-specific changes with larger trends.
  3. Check the choice: Make sure the answer explains the mechanism, pattern, or evidence rather than only repeating a detail.

Multiple scales help scientists connect site-specific changes with larger trends.

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Frequently asked questions about California High School CAST Science Practice Test

Which Science skills are covered?

The page covers high school life science, physical science, Earth and space science, environmental systems, engineering practices, data analysis, and scientific reasoning.

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.