Zoologists warn of an imminent surge in the number of bird species that will become extinct within t...

题目信息

Zoologists warn of an imminent surge in the number of bird species that will become extinct within this century. Nevertheless, these zoologists are wrong. One need only consider the information gathered on native North American raptors, such as bald eagles and peregrine falcons. Several of these species came close to vanishing between 1900 and 1970, but since 1970, the local populations of these raptors have rebounded.

The answer to which of the following questions provides information that would be most helpful in evaluating the argument above?

A:How many species of non-native raptors have been introduced into North America since 1970?

B:What special efforts, if any, have been made to rescue native North American raptors since 1970?

C:How many years' experience do the zoologists have in evaluating patterns of extinction among animals?

D:To what degree have native North American raptors migrated to other parts of the world?

E:How many acres of woodland are set aside each year as bird refuges?

参考答案及共享解析

共享解析来源为网络权威资源、GMAT高分考生等；如有疑问，欢迎在评论区提问与讨论

正确答案： B:What special efforts, if any, have been made to rescue native North American raptors since 1970?

The conclusion of the argument is that the rate of extinction of bird species will not surge in this century. Evidence from native North American raptors (birds of prey) is cited: namely, that even though several such species nearly vanished between 1900 and 1970, the populations of these birds have since rebounded. We are asked to select a question which would, when answered, provide information that would help us evaluate this claim.

(A) This answer choice inquires about the introduction of non-native raptors. However, the argument cites as evidence the resurgence in native raptor populations. Thus, this question does not shed light on the relevance of the evidence.

(B) CORRECT. This question points to an unwarranted assumption on the author's part. The author assumes that the rebound in native North American raptor populations since 1970 was not due to any special effort to save these species. If special efforts have been made to save these raptor species, then one might not be able to generalize this evidence to other bird species or to make predictions about population trends in the next century, using this evidence.

(C) This question is irrelevant: the argument does not depend in any way on the experience of the zoologists. It hinges instead on the trend in raptor populations that the author uses to justify his or her point.

(D) This question is irrelevant. Note that the given evidence states that "local populations of these raptors have rebounded." Thus, population increases of native North American raptors outside of North America are not pertinent.

(E) This question is irrelevant: the argument does not depend in any way on the number of acres of woodland set aside as bird refuges.

_________________

笔记