GED Science Practice Questions: Earth and Its System Components and Interactions

By Achim K. Krull, Dale E. Shuttleworth, Murray Shukyn

Our planet is made up of four basic systems: atmosphere, biosphere, hydrosphere, and geosphere. When these systems interact with each other, the results can be pretty amazing—and sometimes scary (think: volcanoes, tidal waves, and earthquakes); no surprise, then, that some questions on the GED Science test will focus on these interactions.

The following practice questions are typical of what you’ll run into. In both questions, you start by reading a brief passage, and then you have to answer a question based on the information in the passage. Keep in mind that the GED won’t give you questions that require extra, in-depth knowledge of a topic; all the information you need should be in the supplied text.

Practice questions

The first question refers to the following excerpt from NASA’s Science website.

Examples of the types of forecasts that may be possible are: the outbreak and spread of harmful algal blooms, occurrence and spread of invasive exotic species, and productivity of forest and agricultural systems. This Focus Area also will contribute to the improvement of climate projections for 50–100 years into the future by providing key inputs for climate models. This includes projections of future atmospheric CO2 and CH4 concentrations and understanding of key ecosystem and carbon cycle process controls on the climate system.

  1. Long-term forecasts of this type are important to people because

    A. they will help hunters know when their favorite sport will become impossible
    B. they will allow scientists to develop research projects that will address the consequences of dramatic climate change
    C. people will know what type of winter clothing to buy for their children
    D. it will spur research into more efficient subway systems

    The second question refers to the following excerpt from the U.S. Environmental Protection Agency’s website on climate change.

    A food web is made up of predators and prey that interact in a habitat or ecosystem. The impact of climate change on a particular species can ripple through a food web and affect a wide range of other organisms…. Declines in the duration and extent of sea ice in the Arctic leads to declines in the abundance of ice algae, which thrive in nutrient-rich pockets in the ice. These algae are eaten by zooplankton, which are in turn eaten by Arctic cod, an important food source for many marine mammals, including seals. Seals are eaten by polar bears.

  2. The information in the passage implies that a rise in Arctic temperature may result in

    A. an increase in the nutrient-rich pockets in the ice
    B. a decline in the number of polar bears
    C. an extension of the sea ice
    D. an increase in the species of zooplankton

Answers and explanations

  1. The correct answer is Choice (B).

    More accurate forecasts will allow scientists to work on experiments to address the changes that may be coming. Choices (A) and (C) may be possibilities but aren’t mentioned in the passage. Choice (D) is probably a good general idea but has nothing to do with the passage.

  2. The correct answer is Choice (B).

    The passage explains the ripple effect of a food web: It can be reasonably inferred that a rise in Arctic temperature will cause a decline in the extent of sea ice, which will lead to fewer ice algae. Fewer ice algae will lead to fewer zooplankton, which will lead to fewer cod, which will lead to fewer seals. Without a sufficient diet of seals, polar bear populations will decline.