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标题: PREP旧CR1----48 寄生黄蜂与寄主之间不得不说的故事 [打印本页]

作者: rebecw    时间: 2011-5-2 09:31     标题: PREP旧CR1----48 寄生黄蜂与寄主之间不得不说的故事

48.



Parasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg.If they laid too many eggs in a host egg, the developing wasp larvae would compete with each other to the death for nutrients and space.If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae.








Which of the following conclusions can properly be drawn from the information above?








(A) The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp's egg-laying behavior.




(B) Host insects lack any effective defenses against the form of predation practiced by parasitic wasps.




(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species.




(D) Failure to lay enough eggs would lead to the death of the developing wasp larvae more quickly than would laying too many eggs.




(E) Parasitic wasps use visual clues to calculate the size of a host egg.


OA:A

很难理解为什么。最小的寄主的卵就能提供营养也不怕腐烂了么
为什么。。。
求牛人解释。。。



作者: momohe    时间: 2011-5-2 20:40

因为那个寄主相对于卵的数量来说要不大不小啊
作者: momohe    时间: 2011-5-2 20:41

可是我最开始选b,这个题好难
作者: rebecw    时间: 2011-5-3 21:51

我突然有一种顿悟的感觉。。。因为过分纠结于smallest.
题干说了有多种多样的寄主,所以A是选择其中的一种寄主的卵做推断,并不是

纠结于他的尺寸。。

B是原文没提到
C原文没提学经验
D原文也没提两种结果之间的关系
E也没被提到。。
如果用排除法做的比较方便快捷。。
作者: eeheaven    时间: 2011-5-5 06:27

还是不太明白~有NN解释一下吗?
作者: citidandan    时间: 2011-5-15 19:26

This is a must be true type of question.
A is the correct answer. The stimulus says "Parasitic wasps lay their

eggs directly into the eggs of various host insects in exactly the

right numbers for any suitable size of host egg." If so, the wasp can

adjust the number of eggs laid according to the size of the host egg.

So you simply sit next to the host eggs and count how many eggs the

parasitic wasp lays. Make a chart and compare. The host eggs

receiving the lowest amount of parasit eggs would be the smallest

host egg.
作者: eeheaven    时间: 2011-5-16 06:29

get it ~ thx




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