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The primary purpose of the passage is to
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The challenge referred to in the highlighted material pertains primarily to which of the following?
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It can be inferred from the passage that Watson and Kennedy base their view about women's involvement in plant domestication in the Eastern Woodlands in part on
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Important historical differences between Europe and North America may explain why many European migratory songbirds, in contrast to North American migratory songbirds, thrive in forest habitats fragmented by human activity. First, the Pleistocene glaciations may have been more severe in Europe than in North America. [hl:2]Virtually all Europe's forests were erased during the most recent Ice Age[/hl:2]. Any European songbirds dependent upon large, intact blocks of forest were unlikely to survive. In the southern part of North America, however some forests managed to persist through the coldest times, to the advantage of some forest-dwelling songbirds. Second, European forests were being abused by humans for thousands of years before the North American forests were. Consequently, European birds have had more time to adapt to a human-dominated landscape.
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According to the passage, which of the following is true about today's European migratory songbirds?
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In the author's argument, the observation made in the highlighted portion of the passage primarily serves to
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In the Lake Ontario food chain, small fish called alewives are prey for predator fish such as salmon. Any successful effort to reduce pollution in Lake Ontario will also result in a reduced alewife population, but reductions of that population will not, as some have feared, lead to smaller populations of salmon in Lake Ontario, since________.
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Which of the following most logically completes the argument?
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Livestock-grazing programs in arid zones that are based on the equilibrium view of rangelands-that grazing-induced land degradation will occur if livestock numbers exceed the availability of food-have failed. Contrary to the equilibrium view, traditional pastoral systems of land use are more appropriate. Such systems involve a high degree of opportunism to cope with unpredictable rainfall and fluctuating food distribution. Livestock mobility relieves areas of concentration and allows herds to exploit unevenly distributed resources. A strategy of managing multiple livestock species allows optimal use of these variable grazing resources. These approaches to land use are similar to those recommended by [hl:1]nonequilibrium models[/hl:1], which assume that plant dynamics in arid zones are influenced more by rainfall than by grazing.
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According to the passage, the equilibrium view of rangelands is defined in terms of the relationship between
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For the following question, consider each of the choices separately and select all that apply.
The passage suggests that proponents of "nonequilibrium models" would agree with which of the following statements about grazing-induced land degradation in arid zones?
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Dartmoor and Bodmin Moor in southwest England are for many the typical granite landscape: open, treeless, grassy, with abundant rock outcrops including tors (rocky pinnacles)and extensive block and boulder fields. Blanket peats and poor, difficult-to-use soils add to the impression of little human interference. In fact, the granite uplands of southwest England have a long history of human impact, and their present-day landscape contains few natural ingredients other than tors and boulders. The shaping of this land began in Neolithic times, more than 5,000 years ago, but accelerated approximately 4,000 years ago, during the Bronze Age. Neolithic and Bronze Age stone monuments appear to be the main witnesses to human presence, but the land cover is the most impressive legacy of human impact.
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It can be inferred that many people assume which of the following about the landscapes of Dartmoor and Bodmin Moor?
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For the following question, consider each of the choices separately and select all that apply.
According to the passage, which of the following factors have contributed to the impression that humans have had little impact on Dartmoor and Bodmin Moor?
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Lichens consist of a fungus and an alga living in symbiotic union. Testing the widely held hypothesis that lichen-forming fungi are a closely knit, peripheral group of fungi, a team of scientists compared DNA sequences from 10 lichen-forming and 65 non-lichen-forming fungus species. These scientists classified the lichen forming fungi into five kinds that were more closely related to kinds of non-lichen-forming fungi than to one another. The closest relatives of the lichen-forming kinds included some fungi that benefit, and others that cause disease to, associated organisms. Therefore, lichen-forming fungi probably evolved from various species whose effects on associated organisms ranged from benign to malignant. Furthermore, lichen-forming fungi seem to have given rise to other fungi that act as [hl:2]harmful parasites on lichens themselves[/hl:2]. These considerations undermine the long-standing hypothesis that symbiotic relationships normally evolve in an orderly progression from those that are harmful to one partner to those that are mutually beneficial.
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The primary concern of the passage is to
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The author refers to "harmful parasites on lichens themselves" in order to
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Which of the following statements about lichen-forming fungi can be inferred from the passage?
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In California's Mojave Desert, archaeologists found two fluted projectile points, one on the surface. one buried, both similar to classic Clovis stone points from the American Plains. They obtained [hl:1]a radiocarbon date of 8,470[/hl:1] years from material associated with the buried point, a date far more recent than the known time range for Clovis points. There are three ways of accounting for this date. First, it is possible that fluted points were in use in this region around 8,470 years ago. Second, this point may somehow have been deposited at the California site long after its creation. Third, the 8,470-year date may be wrong; a second date from the same context providing an age of 4,360 years was rejected by archaeologists as incorrect.
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According to the passage, which of the following statements is true about "a radiocarbon date of 8,470 years"?
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