DSST® practice test

Free DSST Environmental Science Practice Test (2026)

This is a set of 25 original practice questions that follow the official DSST Environmental Science content outline and its topic weights, each with a short explanation. Answer all 25, then read the explanations to see which topics need more study.

  • 25 questions
  • 5 topics from the official outline
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The practice test

25 questions

Question 1 of 25In a food chain, only about 10 percent of the energy at one trophic level is passed on to the next. If plants in a field capture 10,000 units of energy, about how much reaches the hawks that eat snakes that eat mice that eat the plants?
Question 2 of 25Fertilizer runoff causes algae to bloom in a lake. When the algae die and decompose, the water loses oxygen and fish die. This process is called
Question 3 of 25A student tests whether fertilizer affects bean plant growth. She gives some plants fertilizer and others none, and measures their height. In this experiment, plant height is the
Question 4 of 25Integrated pest management (IPM) controls crop pests mainly by
Question 5 of 25Clownfish live among the stinging tentacles of sea anemones, which protect them, and the fish in turn clean the anemone and drive off some predators. This relationship is
Question 6 of 25The 'tragedy of the commons,' described by Garrett Hardin in 1968, refers to
Question 7 of 25DDT sprayed in small amounts reached high concentrations in eagles and other birds of prey, causing thin eggshells. This build-up of a toxin at higher levels of a food chain is called
Question 8 of 25Plowing across a slope along its natural elevation lines, rather than straight up and down it, mainly helps to
Question 9 of 25A species whose effect on its ecosystem is much larger than its numbers suggest, such as the sea otter that keeps sea urchins from destroying kelp forests, is called a
Question 10 of 25Chlorofluorocarbons (CFCs), once widely used in refrigerators and aerosol cans, harm the environment mainly by
Question 11 of 25Which feature best separates a scientific claim from a pseudo-scientific one?
Question 12 of 25The environmental justice movement in the United States grew out of protests in the early 1980s, such as in Warren County, North Carolina, against
Question 13 of 25Which of the following is a renewable resource when managed well?
Question 14 of 25Lichens and mosses that colonize bare rock left behind by a retreating glacier are the first stage of
Question 15 of 25Sulfur dioxide and nitrogen oxides released mainly by burning fossil fuels in power plants and vehicles are the main causes of
Question 16 of 25The Montreal Protocol (1987) is often called the most successful international environmental agreement because it
Question 17 of 25In a municipal wastewater treatment plant, secondary treatment mainly
Question 18 of 25A population of deer grows quickly at first and then levels off as food and space run short. The population size where it levels off is called the
Question 19 of 25Worldwide, the leading cause of species extinction and loss of biodiversity today is
Question 20 of 25Aldo Leopold's 'land ethic' holds that
Question 21 of 25The federal law known as Superfund (CERCLA, 1980) was passed mainly to
Question 22 of 25Bacteria in soil and in the root nodules of legumes such as beans convert nitrogen gas from the air into forms plants can use. This process is
Question 23 of 25Under the National Environmental Policy Act (NEPA) of 1970, a federal agency planning a major project must
Question 24 of 25The IPAT equation is used to describe environmental impact. In I = P × A × T, the letters P, A and T stand for
Question 25 of 25Which device is commonly used in coal-fired power plants to remove sulfur dioxide from smokestack gases?

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