Practice Exam 2 - Environmental Science - page 268

products, overall emissions depend on the source of the electricity used for electrolysis. The chemical
equation for this reaction is: 2H 2 O → 2H 2 + O 2 .
14. D Both passive and active solar energy use some form of heat-trapping material to capture incoming
solar radiation. With passive solar energy, the heat-trapping materials—including brick, concrete, and
tile—absorb solar radiation directly. In active solar collection, solar collectors are used to capture heat
from the sun. The solar panels are made of a dark metal that absorbs the heat, which is then transferred
to a liquid circulating throughout an area, heating a building or water.
15. E Hydropower uses a dam to control water flow, generating power as water is released from the dam to
power turbines.
16. B The Green Revolution brought new farming techniques, crop varieties, and increased food produc-
tion. During this time, agricultural techniques were industrialized and the processes made more effi-
cient. Increased yield was attained from each plot of land. Selectively breeding crops for specific traits
helped to make more pest- and disease-resistant strains.
17. A Agriculture and deforestation are the two main contributors to soil degradation worldwide. When
forests are cleared, the soil is exposed to wind and water, which can lead to erosion. Agriculture re-
moves the protective cover of vegetation on soil, making the soil prone to erosion as well. Topsoil
erosion reduces soil nutrients and its ability to retain water.
18. B Nuclear energy produces the least amount of greenhouse gas emissions relative to fossil fuels and
biomass since combustion is not part of the nuclear process. The downside of nuclear energy, though, is
the production of radioactive toxic waste.
19. A Chaparral ecosystems are adapted to frequent wildfires. Some vegetation found there has a protect-
ive coating to help resist fire damage, while other types of plants and trees germinate from the extreme
heat of fire.
20. C Net primary production is the amount of energy available to heterotrophs. This represents the
amount of energy from a plant available to consumers after the plant has used some energy through cel-
lular respiration to meet its own energy needs.
21. E Zebra mussels were introduced to the United States through ships entering the Great Lakes. Because
they had few natural limiting factors in the new environment, this invasive species proliferated. The re-
percussions of this invasion have been far-reaching and expensive. The zebra mussels are small, so they
can get inside pipes and clog them; cling to docks, buoys, and boat engines; and damage fishing equip-
ment.
22. C Specialists fill a narrow niche and have specific requirements for survival. These organisms can be
affected easily by environmental changes, so they are more prone to extirpation and extinction.
23. D Organisms pass on their genes through reproduction. To do so, organisms must survive to reproduct-
ive age. Adaptations that allow this survival are coded in an organism's genes, so well-adapted organ-
isms survive to reproduce and pass on these successful genes to their offspring. This is the process of
natural selection.
24. A The development of long tongues over generations reflects directional speciation, during which one
extreme of a trait is selected. This is in contrast to disruptive selection, in which extreme traits are
favored in either direction (extremely short or extremely long tongues), or stabilizing selection in which
the middle ground between two versions of a trait is reflected (a mid-length tongue).