Q22:

In a certain wildlife park, park rangers are able to track the movements of many rhinoceroses because those animals wear radio collars. When, as often happens, a collar slips off, it is put back on. Putting a collar on a rhinoceros involves immobilizing the animal by shooting it with a tranquilizer dart. Female rhinoceroses that have been frequently recollared have significantly lower fertility rates than uncollared females. Probably, therefore, some substance in the tranquilizer inhibits fertility.

Which of the following is an assumption on which the argument depends?

1. The dose of tranquilizer delivered by a tranquilizer dart is large enough to give the rangers putting collars on rhinoceroses a generous margin of safety.
2. The fertility rate of uncollared female rhinoceroses in the park has been increasing in the past few decades.
3. Any stress that female rhinoceroses may suffer as a result of being immobilized and handled has little or no negative effect on their fertility.
4. The male rhinoceroses in the wildlife park do net lose their collars as often as the park’s female rhinoceroses do.
5. The tranquilizer used in immobilizing rhinoceroses is the same as the tranquilizer used in working with other large mammals.

原文說: 拿被recollared的犀牛與uncollared的犀牛的生育力做比較,認為因為是tranquilizer,所以導致recollared犀牛的生育力降低

要找assumption

正確答案C: 任何促使犀牛無法動彈的力量都不會損害到犀牛的生育力

可是,tranquilizer不就是促使犀牛無法動彈的力量嗎??

C的選項不就是把stress包括在其中??

如果這樣,怎麼可能由這個assumption推出結論呢??

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If the stress Female rhinoceroses suffered does have effect on

their fertility, then the author could not for sure say that

"Probably, therefore, some substance in the tranquilizer inhibits

fertility."

We can think it in this way:

A is short for Substance. B is short for Stress.

The author try to prove that A lead to the result, but before that

he must state that B could not lead to the result. If not, his

conclusion will not be convincing.

So option C appear to be the most suitable.