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标题: 5月12日 求助 prep 48 [打印本页]

作者: miffycn    时间: 2007-5-12 10:01
标题: 5月12日 求助 prep 48

48.       (34221-!-item-!-188;#058&007550)

 

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 (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.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.

 

(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.

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

这道题是旧题 不过我还是忘了答案是什么了,因为第一次没错好象

选A 我不明白最小的宿主的蛋的尺寸可以理论上从wasp`s egg-laying behavior决定.

到底是谁决定谁  我怎么觉得文中的意思是 paracitc 下蛋的个数是由宿主蛋的大小决定的呢? 下多了,会竞争导致死亡 下少了 由于宿主细胞腐烂导致幼虫死亡,大家帮我看看吧~~~

我选的D

 


作者: vivian_dong    时间: 2008-5-7 00:05
同问
作者: lyen_wang    时间: 2009-2-22 02:06
我也有同样的疑问 不知有谁可以解答一下
作者: hansomecd    时间: 2009-2-22 13:41

原文:exactly the right numbers for any suitable size of host egg

注意这个suitable,如果Parasitic wasps对于size of host egg 有无限的调节能力,那么Parasitic wasps 就可以在任何size的蛋里面寄宿

正因为本身Parasitic wasps产卵的量也有一个限制区间:A-B ,即一次产卵至少有A个,至多B个,所以对应的有size of egg A'和 B'

所以最小的size A’可知。

D讲的两种不合适导致的死亡速率,无关的


作者: raphael1234    时间: 2009-8-1 20:36
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