lsat-25-2-22

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22.   Biologist: Some speculate that the unusually high frequency of small goats found in island populations is a response to evolutionary pressure to increase the number of goats so as to ensure a diverse gene pool. However, only the reproductive success of a trait influences its frequency in a population. So, the only kind of evolutionary pressure that can reduce the average size of the members of a goat population is that resulting from small goats achieving greater reproductive success than their larger cousins.

The biologist’s view, if true, provides the most support for which one of the following?

(A) The evolutionary pressure to ensure a diverse gene pool could have the effect of increasing the frequency of a gene for small size.

(B) The unusual frequency of small goats in island populations is not a result of the greater reproductive success small goats possess when space is limited.

(C) Contrary to what some believe, large goats achieve greater reproductive success than small goats even when space is limited.

(D) The evolutionary pressure to ensure diverse gene pool does not have the effect of increasing the frequency of a gene for small size.（D）

(E) A diverse gene pool cannot be achieved in a goat population unless the average size of its members is reduced.

不太明白这道题前后是怎么推的？

dphxmg

someone argues that a diverse gene pool of small goats explains away an unsusal proportion of small goats in island populations of goats.

Other argue that it is reproductive success of small goats rather than their diverse gene pool that can explain the higer proportion of small goats among island goats.

Conclusion: the second point is correct.

the three paragraphs above are the paraphrasing of the stimulus.

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明白了，谢谢dphxmg