• 60 questions

APES AP Practice Test

An unofficial AP Environmental Science practice test: multiple-choice questions on all nine units, with the calculations worked out.

About what share of all of Earth's water is held in the oceans?

Pick an answer, then press Check answer. Then you see Correct or Not quite, with the reason. Keys: A to D pick, Enter checks.

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Exam mode: 40 questions, 45 minutes.

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Unofficial practice questions, not affiliated with the College Board. Bank checked October 10, 2026.

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All 60 questions

Unit 1: The Living World: Ecosystems 4

  • About what share of all of Earth's water is held in the oceans? U.S. Geological Survey, Water Science School, "How Much Water is There on Earth?", read October 10, 2026; course topic 1.7
  • In the nitrogen cycle, which step turns nitrogen gas from the air into ammonia that living things can take up from the soil? AP Environmental Science Course and Exam Description, effective fall 2026, topic 1.5 (ERT-1.E.1, ERT-1.E.2)
  • Producers in a meadow store 40,000 kcal of energy per square meter each year. By the 10% rule, about how much of that energy reaches the secondary consumers? Worked from the numbers in the question; AP Environmental Science Course and Exam Description, effective fall 2026, topic 1.10 (ENG-1.C.1)
  • Which biogeochemical cycle has no significant atmospheric component? AP Environmental Science Course and Exam Description, effective fall 2026, topic 1.6 (ERT-1.F.2, ERT-1.F.3)
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Unit 2: The Living World: Biodiversity 4

  • A disease leaves only a few dozen survivors of a once-large population. What is the most likely lasting effect of this bottleneck? AP Environmental Science Course and Exam Description, effective fall 2026, topic 2.1 (ERT-2.A.2)
  • Ecologists remove one predator species from a tide pool, and the mix of the other species there changes sharply. A species with such an outsized role in shaping its community is called AP Environmental Science Course and Exam Description, effective fall 2026, topic 2.7 (ERT-2.I.2, ERT-2.I.3)
  • Trout in a stream survive only where the water stays within a narrow band of temperature. The range of conditions an organism can stand without injury or death is its AP Environmental Science Course and Exam Description, effective fall 2026, topic 2.4 (ERT-2.F.1)
  • Why are many island species at special risk when an invasive species arrives? AP Environmental Science Course and Exam Description, effective fall 2026, topic 2.3 (ERT-2.E.1)

Unit 3: Populations 7

  • A country has a crude birth rate of 28 per 1,000 people and a crude death rate of 9 per 1,000. What is its rate of natural increase, as a percentage? Worked from the numbers in the question; AP Environmental Science Course and Exam Description, effective fall 2026, topic 3.8 (EIN-1.C.4)
  • A country's population grows by 2% a year. By the rule of 70, about how long will it take to double? Worked from the numbers in the question; AP Environmental Science Course and Exam Description, effective fall 2026, topic 3.8 (EIN-1.C.4)
  • A deer herd on an island grows past the island's carrying capacity. What usually follows this overshoot? AP Environmental Science Course and Exam Description, effective fall 2026, topic 3.4 (ERT-3.D.1, ERT-3.E.1)
  • An age structure diagram has a very wide base and narrows quickly toward the top. The population it shows is most likely AP Environmental Science Course and Exam Description, effective fall 2026, topic 3.6 (EIN-1.A.1, EIN-1.A.2)
  • An r-selected insect lays thousands of eggs and gives them no care. Which survivorship curve does such a species typically follow? AP Environmental Science Course and Exam Description, effective fall 2026, topic 3.3 (ERT-3.C.1, ERT-3.C.2)
  • In the demographic transition model, what happens to a country's birth and death rates as it moves from a pre-industrial to an industrialized economy? AP Environmental Science Course and Exam Description, effective fall 2026, topic 3.9 (EIN-1.D.1)
  • Which set of traits describes a K-selected species? AP Environmental Science Course and Exam Description, effective fall 2026, topic 3.2 (ERT-3.B.1, ERT-3.B.2)

Unit 4: Earth Systems and Resources 7

  • A city receives its most solar radiation on its longest summer day and its least on its shortest winter day. What causes this yearly swing? AP Environmental Science Course and Exam Description, effective fall 2026, topic 4.7 (ENG-2.A.4, ENG-2.A.5)
  • A soil texture triangle sorts soils by their percentages of which three kinds of particle? AP Environmental Science Course and Exam Description, effective fall 2026, topic 4.3 (ERT-4.C.4)
  • Along one fault, two plates grind horizontally past each other, and crust is neither made nor destroyed. Which hazard does this kind of boundary mainly produce? U.S. Geological Survey, This Dynamic Earth, "Understanding plate motions", read October 10, 2026; course topic 4.1 (ERT-4.A.1, ERT-4.A.2, ERT-4.A.3)
  • Because Earth rotates on its axis, air circulating in the Northern Hemisphere is deflected in which direction? NOAA National Ocean Service, Currents Tutorial, "The Coriolis Effect", read October 10, 2026; course topic 4.5
  • During El Niño, what happens to the Pacific trade winds and to upwelling off the west coast of the Americas? NOAA National Ocean Service, "What are El Niño and La Niña?", read October 10, 2026; course topic 4.9
  • Moving up through the stratosphere, the air gets warmer instead of colder. What does NOAA give as the reason? NOAA JetStream, "Layers of the Atmosphere", read October 10, 2026; course topic 4.4 (ERT-4.D.2)
  • Which description fits a watershed? NOAA National Ocean Service, "What is a watershed?", read October 10, 2026; course topic 4.6

Unit 5: Land and Water Use 8

  • As pavement and rooftops spread across a watershed, what happens to flooding? U.S. Geological Survey, Water Science School, "Impervious Surfaces and Flooding", read October 10, 2026; course topic 5.10 (EIN-2.M.3)
  • How much of a renewable resource can be taken while the available supply stays the same is called the AP Environmental Science Course and Exam Description, effective fall 2026, topic 5.12 (STB-1.A.2, EIN-2.N.1)
  • In a dry region, irrigation water evaporates from a field year after year and leaves its dissolved salts behind. What is this process called? AP Environmental Science Course and Exam Description, effective fall 2026, topic 5.5 (EIN-2.F.6)
  • Ranchers share an open pasture. Each adds cattle for personal gain until the grass is gone. What does this illustrate? AP Environmental Science Course and Exam Description, effective fall 2026, topic 5.1 (EIN-2.A.1)
  • Under integrated pest management, what is set before any pest control action is taken? U.S. Environmental Protection Agency, "Integrated Pest Management (IPM) Principles", read October 10, 2026; course topic 5.14
  • Which irrigation method applies water directly to the root zone of plants through emitters or perforated tubing under low pressure? U.S. Geological Survey, Water Science School, "Irrigation Methods: A Quick Look", read October 10, 2026; course topic 5.5 (EIN-2.F.5)
  • Which is a recognized drawback of aquaculture? AP Environmental Science Course and Exam Description, effective fall 2026, topic 5.16 (STB-1.F.1, STB-1.F.2)
  • Which practice is a soil conservation method? AP Environmental Science Course and Exam Description, effective fall 2026, topic 5.15 (STB-1.E.1, EIN-2.D.1, EIN-2.B.1)

Unit 6: Energy Resources and Consumption 8

  • A 1,500-watt space heater runs 4 hours a day for 30 days. Electricity costs $0.12 per kilowatt-hour. What does it cost to run the heater for those 30 days? Worked from the numbers in the question; U.S. Energy Information Administration, Energy Explained, "Measuring electricity", read October 10, 2026; AP Environmental Science Course and Exam Description, effective fall 2026, topic 6.13 (ENG-3.T.1)
  • A hydrogen fuel cell combines hydrogen with oxygen. Besides electricity and a little heat, what does it produce? U.S. Energy Information Administration, Energy Explained, "Use of hydrogen", read October 10, 2026; course topic 6.11 (ENG-3.P.1)
  • A waste sample holds 120 grams of a radioactive isotope whose half-life is 25 years. How much of the isotope remains after 75 years? Worked from the numbers in the question; AP Environmental Science Course and Exam Description, effective fall 2026, topic 6.6 (ENG-3.H.2)
  • How do nuclear power plants release energy from uranium? U.S. Energy Information Administration, Energy Explained, "Nuclear explained", read October 10, 2026; course topic 6.6 (ENG-3.G.1)
  • Uranium for power plants has to be mined. How does the EIA classify nuclear energy, and why? U.S. Energy Information Administration, Energy Explained, "Sources of energy", read October 10, 2026; course topic 6.1 (ENG-3.A.1, ENG-3.G.4)
  • What is the largest component of natural gas? U.S. Energy Information Administration, Energy Explained, "Natural gas explained", read October 10, 2026; course topic 6.3 (ENG-3.C.4)
  • Which is a recognized environmental drawback of wind turbines? U.S. Energy Information Administration, Energy Explained, "Wind energy and the environment", read October 10, 2026; course topic 6.12 (ENG-3.S.1)
  • Which rank of coal generally has the highest heating value? U.S. Energy Information Administration, Energy Explained, "Coal explained", read October 10, 2026; course topic 6.3

Unit 7: Atmospheric Pollution 5

  • A catalytic converter changes carbon monoxide, nitrogen oxides and hydrocarbons in engine exhaust into which less harmful products? AP Environmental Science Course and Exam Description, effective fall 2026, topic 7.6 (STB-2.G.3)
  • During a thermal inversion, air at the surface is cooler than the air above it. What is the effect on air quality? AP Environmental Science Course and Exam Description, effective fall 2026, topic 7.3 (STB-2.C.1, STB-2.C.2)
  • The EPA's acid rain page traces about two thirds of the sulfur dioxide in the atmosphere to which source? U.S. Environmental Protection Agency, "What is Acid Rain?", read October 10, 2026; course topic 7.7
  • Ground-level ozone is not emitted directly. It forms when which two kinds of pollutant react in sunlight? U.S. Environmental Protection Agency, "Ground-level Ozone Basics", read October 10, 2026; course topic 7.2
  • Radon is a radioactive gas that seeps into buildings from rock and soil. The EPA names it the second leading cause of which disease in the United States? U.S. Environmental Protection Agency, "Health Risk of Radon", read October 10, 2026; course topic 7.5 (STB-2.F.2)

Unit 8: Aquatic and Terrestrial Pollution 6

  • A power plant returns warm cooling water to a river. What will most likely happen to dissolved oxygen just downstream? U.S. Geological Survey, Water Science School, "Dissolved Oxygen and Water", read October 10, 2026; course topic 8.6 (STB-3.G.1, STB-3.G.2)
  • Fertilizer runoff enters a lake and an algal bloom follows. Why do fish then die? U.S. Geological Survey, Water Science School, "Phosphorus and Water", read October 10, 2026; course topic 8.5 (STB-3.F.2)
  • In a modern municipal landfill, what is the purpose of the composite liner along the bottom and sides? U.S. Environmental Protection Agency, "Municipal Solid Waste Landfills", read October 10, 2026; course topic 8.9 (STB-3.K.4)
  • In a sample lake, a pesticide measures 0.04 parts per million in plankton, 0.5 in small fish and 25 in fish-eating birds. What is this rise at each higher trophic level called? AP Environmental Science Course and Exam Description, effective fall 2026, topic 8.8 (STB-3.I.1, STB-3.I.2)
  • In tests on one species, chemical A has an LD50 of 5 mg per kg of body mass and chemical B has an LD50 of 500 mg per kg. Which statement is correct? AP Environmental Science Course and Exam Description, effective fall 2026, topic 8.12 (EIN-3.A.1)
  • Which of these is a point source of water pollution? U.S. Environmental Protection Agency, "Summary of the Clean Water Act", read October 10, 2026; course topic 8.1 (STB-3.A.1, STB-3.A.2)

Unit 9: Global Change 11

  • A reef turns white during a marine heat wave. What has happened to its corals? NOAA National Ocean Service, "What is coral bleaching?", read October 10, 2026; course topic 9.6 (STB-4.G.3)
  • Arctic sea ice melts, the darker ocean absorbs more solar energy, and the extra warming melts more ice. What is this cycle an example of? AP Environmental Science Course and Exam Description, effective fall 2026, topic 9.5 (STB-4.F.7, STB-4.F.8)
  • Carbon dioxide has a global warming potential of 1. Using a 100-year global warming potential of 28 for methane, a leak of 5 tons of methane equals how many tons of carbon dioxide equivalent? Worked from the numbers in the question; AP Environmental Science Course and Exam Description, effective fall 2026, topic 9.3 (STB-4.D.1)
  • Compared with its level before the Industrial Revolution, about how much higher is the concentration of carbon dioxide in the atmosphere now? NOAA Climate.gov, "Climate change: atmospheric carbon dioxide", read October 10, 2026; course topic 9.4
  • Global sea level is rising. Besides the melting of glaciers and ice sheets on land, what other major cause does NOAA name? NOAA National Ocean Service, "Is sea level rising?", read October 10, 2026; course topic 9.4
  • HFCs replaced CFCs because they do not deplete ozone. Why did the 2016 Kigali Amendment add a phase-down of HFCs? U.S. Environmental Protection Agency, "International Treaties and Cooperation about the Protection of the Stratospheric Ozone Layer", read October 10, 2026; course topic 9.2 (STB-4.B.1)
  • The ocean absorbs about 30 percent of the carbon dioxide released to the atmosphere. What is the effect on seawater? NOAA National Ocean Service, "What is Ocean Acidification?", read October 10, 2026; course topic 9.7
  • What does the stratospheric ozone layer mostly absorb? U.S. Environmental Protection Agency, "Basic Ozone Layer Science", read October 10, 2026; course topic 9.1
  • Which agreement, signed in 1987, began the international phaseout of ozone-depleting substances? U.S. Environmental Protection Agency, "International Treaties and Cooperation about the Protection of the Stratospheric Ozone Layer", read October 10, 2026; course topic 9.2
  • Which is a common way for an aquatic invasive species to reach a new region? NOAA National Ocean Service, "What is an invasive species?", read October 10, 2026; course topic 9.8
  • Which U.S. law, passed in 1973, protects listed plants and animals and the habitats in which they are found? U.S. Environmental Protection Agency, "Summary of the Endangered Species Act", read October 10, 2026; course topic 9.9 (EIN-4.B.5)

How this list was compiled: Our own questions, written to the nine units of the College Board's AP Environmental Science Course and Exam Description, effective fall 2026, https://apcentral.collegeboard.org/media/pdf/ap-environmental-science-course-and-exam-description.pdf, and to the exam page https://apcentral.collegeboard.org/courses/ap-environmental-science/exam, both read 2026-10-10. Each fact was read on 2026-10-10 in the place named under its question: a page of the U.S. Environmental Protection Agency, the National Oceanic and Atmospheric Administration, the U.S. Geological Survey or the U.S. Energy Information Administration, or a numbered essential knowledge statement of the Course and Exam Description. Every calculation was recomputed from the numbers in its question. Licence: Own work.

How it works

This APES practice test, on screen or printed, has 60 questions of our own, spread over the nine units of AP Environmental Science in the exam's proportions. It is unofficial and not affiliated with or endorsed by the College Board.

Read the full guide

The real multiple-choice section

By the College Board's exam page, read October 10, 2026, Section I of the AP Environmental Science Exam asks 80 multiple-choice questions in 1 hour 30 minutes for 60% of the score. Exam mode is half that length: 40 questions in 45 minutes.

The nine units

Units 1 and 2 each carry 6 to 8% of the section, Units 3 to 6 each 10 to 15%, Units 7 and 8 each 7 to 10%, and Unit 9 carries 15 to 20%. The bank follows those shares.

Where the answers come from

Each explanation names where its fact was read: an EPA, NOAA, USGS or Energy Information Administration page, or a numbered statement of the Course and Exam Description. Every calculation was recomputed.

  • Both sections of the real exam allow a calculator, so use one here for the rule of 70, half-lives and kilowatt-hours.
  • The real section also asks sets of questions on a table, graph, map or text source. Here every question stands alone.

Questions and answers

Is this APES AP practice test official?

No. Every question was written for this site from the College Board's published course outline and from public agency pages. None repeats or rewords a real, released or sample exam question, and a result here does not forecast an AP score.

Is there an AP Environmental Science practice test PDF?

Yes, as a printout. Print the question sheet opens 40 questions, half the real section, from all nine units; add more, up to all 60, and tick With answer key. Choose Save as PDF in the print window to keep it as a file.

How long is the AP Environmental Science exam?

2 hours 40 minutes: 1 hour 30 minutes of multiple choice, then 1 hour 10 minutes for the 3 free-response questions. It is a fully digital exam, taken in the Bluebook app.

What units are on the APES exam?

Nine: The Living World: Ecosystems; The Living World: Biodiversity; Populations; Earth Systems and Resources; Land and Water Use; Energy Resources and Consumption; Atmospheric Pollution; Aquatic and Terrestrial Pollution; Global Change.

Does this APES practice test cover the free-response questions?

No, only the multiple choice. The three free-response questions (design an investigation, analyze and interpret quantitative data, analyze an environmental problem doing calculations) are 40% of the exam score and are not practiced here.

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