Practice Exam 1 - Environmental Science - page 233

34. A Wind has kinetic energy (energy of motion). This kinetic energy is converted into electrical energy
through the use of turbines. Wind turns the turbine blades, which rotate an internal shaft. This connects
to a generator that produces electrical energy.
35. D In the 1960s, oil overtook coal as the most commonly used fossil fuel. Oil is used for many pur-
poses, including home heating, transportation, and power plants. Currently the use of natural gas is in-
creasing at the fastest rate.
36. B Exposure to a substance in large doses within a brief period of time is termed acute exposure, while
exposure to small doses over a long period of time is considered chronic exposure. Acute exposure is
usually related to a specific incident or event. Chronic exposure affects an organism gradually over
time, and because of this the source is usually harder to identify.
37. C The dramatic dip in population size represents population destabilization, likely due to limiting
factors in the environment.
38. E Any number of factors could have contributed to this destabilization and drop in population num-
bers. Such factors include disease; temperature extremes; or competition for space, food, and water.
39. A A risk assessment includes a dose-response analysis, which assesses the toxic effects of a substance
on an organism.
40. A In an aquatic environment, succession can occur due to eutrophication. As excess nutrients enter a
lake or pond, plants and organisms grow rapidly. Eventually plants fill the area. With extensive growth
comes a large amount of death and decomposition. Water accumulates dead organic matter over time,
and a moving water source also deposits sediment. Ultimately, this area is likely to become terrestrial
because it has essentially been filled in by dead organic matter and sediment.
41. B Australia suffered an economic depression in the 1920s and 1930s, as did the United States. When
there is a severe economic depression, the total fertility rates typically decline because most people can-
not afford to have children.
42. B As in the United States, Australia experienced an economic boom in the 1940s and 1950s following
World War II. This led to increased total fertility rates and a baby boom.
43. C As with any declining human population, a decrease in population growth could lead to a decrease in
the labor market because there are fewer young people entering the workforce. With fewer people in the
population working and making money, there could be an economic decline.
44. B A tragedy of the commons occurs when an unregulated resource is overexploited unsustainably.
Fisheries cannot always be managed and controlled globally. Therefore, the resource can be over-har-
vested and depleted without proper regulation and monitoring. Because it is in each individual actor's
best interest to act unsustainably, all suffer in the long run.
45. E Heat capacity is the amount of heat necessary to change the temperature of a substance. Thus, it de-
scribes the ability of a substance to retain heat. Water has a high heat capacity, meaning it heats and
cools slowly, and only with the addition or subtraction of large amounts of heat energy. Therefore,
oceans remain at a more constant temperature than land because oceans heat and cool slowly, while
land temperatures change more quickly.
46. D Overworking and overuse of the land can lead to soil salinization in arid regions where high evapor-
ation rates pull salt-laden waters from deeper in the soil to the surface, where salts remain after the wa-
ter content evaporates. Also, dust storms occur when dry, overworked soil becomes airborne. Waterlog-
ging occurs when soils are overwatered and become saturated. Desertification occurs when land in arid