old prep1 cr48

davidliuscu

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 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.

答案：A, 我选的B
不理解为什么A正确

xfi883

题干是指出了一种关系，即寄生虫下蛋的数量和被寄居的虫卵大小成正比。即虫卵大，下蛋多，宠卵小，下蛋少。因而，从寄生虫下蛋的行为中，可以决定虫卵的大小。

davidliuscu

也就是说：如果寄生蜂(parasitic wasp)的产卵行为决定她一次最少产10个卵，所以寄主（host insects ）的卵所含养分必须能供养10个幼蜂。因此：“The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp's egg-laying behavior.”

谢谢斑竹！

q1weruqt

题干是指出了一种关系，即寄生虫下蛋的数量和被寄居的虫卵大小成正比。即虫卵大，下蛋多，宠卵小，下蛋少。因而，从寄生虫下蛋的行为中，可以决定虫卵的大小。

-- by 会员 xfi883 (2011/7/1 9:10:23)

我也懂了谢谢斑竹