Paragraph7：Many ecologists now think that the relative long-term stability of climax communities comes not from diversity but from the “patchiness” of the environment, an environment that varies from place to place supports more kinds of organisms than an environment that is uniform. Alocal population that goes extinct is quickly replaced by immigrants from an adjacent community. Even if the new population is of a different species, it can approximately fill the niche vacated by the extinct population and keep the food web intact.
11．Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incurred choices change the meaning in important ways or leave out essential information.
○Ecologists now think that the stability of an environment is a result of diversity rather than patchiness.
○Patchy environments that vary from place to place do not often have highspecies diversity.
○Uniform environments cannot be climax communities because they do not support as many types of organisms as patchy environments.
○A patchy environment is thought to increase stability because it is able to support a wide variety of organisms.
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发表于 2010-10-26 09:19:32
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