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P1-48

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.

Answer:A

这道题我选的C,看了前人的讨论实在是摸不着头脑。到底A是怎么推出来的呢?最小的宿主的被寄生的卵不是应该有寄生虫卵的大小决定的么?为什么是A说的是由寄生虫的laying behavior决定呢?我看到有的人把size解释为数量,我觉得不太对吧,原文中有明确的number和size的区别阿。希望NN们的解答~~~~~~~~~~~~~~~~~~~~~~

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从题目中我们可以推断出这样的规律:Parasitic wasps的每个幼虫的生存所配给的养分应该在一个区间内。假设一个host egg的size为s1而从wasp在这种host egg的具体产卵数为介于(n1, n2)之间,则每个幼虫合理的养分分配区间为(s1/n2, s1/n1)。因为理论上最小的host egg的size为只产一个卵时所合适的值,即(s1/n2, s1/n1)。而这里s1, n1, n2均可以通过研究wasp's egg-laying behavior得到。从而证明了A的正确性。

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这个....我看得有点似懂非懂,归纳题的解题思路有这样复杂么....

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首先C中的这个learn推不出来

然后就是对于A,这个东西可以根据宿主egg的大小下它们自己的egg,那我们就可以从它们自己的egg数来判断宿主egg的大小喽,最小的不就也能知道了

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好像有点点明白了....

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那为什么不能选B呢?请教NN们~

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归纳题不能出现无关词 defense是问中没有说过的 因此得不出此结论 即便次结论为真 也不是从文中信息

归纳出来的

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