明天考试了 急问一道逻辑题 在线等 谢谢

pipilovelail

明天考试了 急问 在线等！

3.    (24275-!-item-!-188;#058&000768)



The prairie vole, a small North American grassland rodent, breeds year-round, and a group of voles living together consists primarily of an extended family, often including two or more litters.  Voles commonly live in large groups from late autumn through winter; from spring through early autumn, however, most voles live in far smaller groups.  The seasonal variation in group size can probably be explained by a seasonal variation in mortality among young voles.



Which of the following, if true, provides the strongest support for the explanation offered?



(A) It is in the spring and early summer that prairie vole communities generally contain the highest proportion of young voles.

(B) Prairie vole populations vary dramatically in size from year to year.

(C) The prairie vole subsists primarily on broad-leaved plants that are abundant only in spring.

(D) Winters in the prairie voles' habitat are often harsh, with temperatures that drop well below freezing.

(E) Snakes, a major predator of young prairie voles, are active only from spring through early autumn.

不明白，春天蛇多了，可以rodent的族群缺变小了，这不更容易让蛇吃了吗？

为什么选E啊 逻辑思路不理解

keaneice

题干你理解的有些偏差，题目是说春到秋，这群耗子的group数量就小，是因为小耗子少了。问加强
e：就说蛇多了，专吃小耗子，所以正确

flyinhair

只有E中所说现象的发生时间段跟V的族群大小变化周期吻合，其他选项全部都没有涵盖整个周期。所以只有E有关。
如果实在需要一个解释，那可以解释为： 蛇吃V，吃V就会导致V变少，因此原本的一大堆V就变成一小堆V了。

christine919

motarlity->variation in group size
蛇多了，吃掉的young voles多了 所以死掉的多了，group 变小

minertus

楼主的格式 看得我眼花缭乱的....汗死