PrepTest 131, Section 1, Question 13
It is a mistake to think, as ecologists(57 more words not shown)
Which one of the following(9 more words not shown)
- AIt is not(11 more words not shown)
- BNatural selection will(12 more words not shown)
- CNo single set(18 more words not shown)
- DBecause an individual's(13 more words not shown)
- EEcologists once believed(16 more words not shown)
Reading the argument
The author opens by rejecting a prediction: natural selection will eventually produce organisms perfectly adapted to their environments. Why might that be a mistake? If environments keep changing, the attributes that help in one situation might not prepare an organism for another.
That is the reasoning the author develops. An organism can face many different conditions, and no single set of attributes prepares it for every one. Think of how being especially good at one task can come with limits elsewhere. Being as well suited as possible to a particular situation is also different from being perfect under every condition it might encounter.
What we’re looking for
The main-conclusion question asks where those reasons lead. The author uses the impossibility of perfect adaptation to reject the ecologists' prediction about natural selection. So the main point is not merely “perfect adaptation is impossible.” It is the further conclusion that natural selection will never produce the perfectly adapted organisms those ecologists expected.
Working the answers
- A
This is an important supporting claim, and it is supported in turn by the environmental variation discussed afterward. But the argument uses it to establish something further about what natural selection will produce. A stops before that final application.
- BCorrect
This restates the rejection of the ecologists' prediction: natural selection will not eventually produce perfectly adapted individuals. It does not need to repeat the words “it is a mistake.” Saying the predicted result will never occur expresses the author's rejection of that prediction.
- C
This explains why perfect adaptation is impossible: no set of attributes handles every potential condition. It is a reason in the argument's chain of support, not the final claim about natural selection.
- D
This combines an environmental reason with the supporting conclusion that perfect adaptation is impossible. It captures part of the reasoning, but leaves out what that reasoning is used to establish about the outcome of natural selection.
- E
This tells us what ecologists once believed. The author goes on to say that belief was mistaken. Merely reporting the old position leaves out the rejection that the rest of the argument supports.
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