纠结题 求解释

lishb07

25. Which of the following most logically completes the reasoning?

Either food scarcity or excessive hunting can threaten a population of animals. If the group faces food scarcity, individuals in the group will reach reproductive maturity later than otherwise. If the group faces excessive hunting, individuals that reach reproductive maturity earlier will come to predominate. Therefore, it should be possible to determine whether prehistoric mastodons became extinct because of food scarcity or human

hunting, [c1]since there are fossilized mastodon remains from both before and after mastodon populations declined, and__.

(A) there are more fossilized mastodon remains from the period before mastodon populations[c2] began to decline than from after that period

(B) the average age at which mastodons from a given period reached reproductive maturity[c3] can be established from their fossilized remains

(C) it can be accurately estimated from fossilized remains when mastodons became extinct

(D) it is not known when humans first began hunting mastodons

(E) climate changes may have gradually reduced the food available to mastodons

答案是B  不太懂 ，求解释

chasingM7

take this as a support-like question.

Conclusion: it should be possible to determine whether prehistoric mastodons became extinct because of food scarcity or human hunting.

Premises: 1) 缺少食物或人类屠杀会影响种族数量的减少。
        2）如果是食物少，那么生育年龄就晚
        3）如果是屠杀，那么生育年龄就早

结论问可以通过某种方式判断因为什么原因造成的种族数量减少。题目给出一个不同点，就是生育年龄早晚可以得出原因。

B) 说化石可以推算出生育年龄。BINGO~

hope it helps