Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables.These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions.However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time.
Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record?
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AMajor episodes of extinction can result from widespread environmental disturbances that affect numerous different species.
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BCertain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species.
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CSome species become extinct because of accumulated gradual changes in their local environments.
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DIn geologically recent times, for which there is no fossil record.human intervention has changed the pattern of extinctions.
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ESpecies that are widely dispersed are the least likely to become extinct.
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正确答案: A