Practice Exam 1 - Environmental Science - page 235

rounded by various man-made structures such as roadways, canals, shopping centers, and other devel-
opments. Other activities such as deforestation, agricultural development, and rerouting of a water
source also can create habitat islands.
57. A Deforestation is occurring at a rapid rate in both South America and Africa. The tropical rain forests
in these regions provide many economic resources, so the sale of trees and other resources are a way to
bring revenue to the countries. In addition, the rapid rate of population growth in these areas increases
the need for land. This results in forests being cut down to make space for people.
58. C Deforestation was once occurring at a very rapid rate in both Europe and North America, but the de-
struction has slowed and some forest land is actually being regained through successful conservation
and preservation efforts.
59. A In photovoltaic cells, solar energy is converted into electrical energy. Electrons are released as a res-
ult of sunlight illuminating metal within the cell. The electrons then travel toward another piece of met-
al, creating an electric current.
60. D In mutualism, organisms interact in a way that gives each a fitness benefit—in this case, coral
providing shelter for algae, which in turn provides food for the coral through photosynthesis.
61. B Wind varies dramatically from place to place, day to day, and season to season, leaving humans with
no control over when and how much wind is available at a given time.
62. B Large amounts of oil reserves are located in Iran, Iraq, and Saudi Arabia, with close to two-thirds of
the world's oil supply being located in the Middle East.
63. E The use of biomass as a fuel source offers many benefits, but there are downsides as well. One of the
drawbacks is the production of biomass crops used for energy on land that could potentially be used as
crop land for food production. Also, the biomass crops are usually monoculture, with little biodiversity.
64. D The types of coal are defined by their water content, as well as how the coal was formed. The more
heat and pressure under which coal is formed, the more energy per unit volume and the less water it
contains. Peat is wet, moderately compressed organic matter that forms near the surface.
65. E The types of coal are defined by their water content, as well as how the coal was formed. The more
heat and pressure under which coal is formed, the more energy per unit volume and the less water it
contains. Anthracite is the deepest and most compressed form of coal, so it has the highest energy con-
tent per volume.
66. A The types of coal are defined by their water content, as well as how the coal was formed. The more
heat and pressure under which coal is formed, the more energy per unit volume and the less water it
contains. Lignite is formed relatively close to the surface under minimal heat and pressure, so it retains
more water than anthracite but not as much as peat.
67. D Resulting from the decomposition of organic matter, natural gas is produced in an anaerobic envir-
onment within the Earth. It can form either near the surface of the lithosphere or deep within the Earth.
Within the Earth, natural gas is formed under extreme heat and pressure. (If organic matter decomposes
aerobically, it simply rots.)
68. C Developed nations use a disproportionate percentage of energy for transportation, industrial pro-
cesses, and agriculture. In developing countries, energy is still invested mainly in daily activities such
as cooking, indoor heating, industry, and agriculture. As many of the world's nations develop, more en-
ergy is used for transportation and industry.