GWD逻辑题，求解答！

gmat考750

Lyme disease is caused by a bacterium transmitted to humans by deer ticks.  Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected white-footed mice.  However, certain other species on which the larvae feed do not harbor the bacterium.  Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium―and hence the number of people contracting Lyme disease—would likely decline.

Which of the following, if true, most strengthens the argument?

	Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
	There are no known cases of a human's contracting Lyme disease through contact with white-footed mice.
	A deer tick feeds only once while in the larval stage.
	A single host animal can be the source of bacteria for many tick larvae.
	None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

答案是C，个人感觉E也很有道理，

求解答！@

gmat考750

谢谢LS!

anyunww

deer tick在larval阶段只吃一次。导致deer tick吃到的特定bacterium的概率下降

priscillalxl

一只幼虫只在一只动物上寄生。其他物种的数量增加了，举例来说，原来有5只鼠+5只羊（代指其他物种），那幼虫寄居在鼠身上的概率是1/2；现在变成95只羊，5只鼠，那幼虫寄居在鼠身上的概率下降为5%，因为幼虫如果寄生在羊身上，就不可能再去寄生在鼠身上。如此这般，在虱子总量不变的情况下，虱子携带病菌的概率就下降了。

gmat考750

None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.
E选项没提到结论中的Lyme disease，other bacteria会引起Lyme disease吗 未知 和结论关联度低

-- by 会员 luyihui417 (2011/8/23 16:32:20)

能不能解释下C是怎么关联的？？谢谢@@@

luyihui417

None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.
E选项没提到结论中的Lyme disease，other bacteria会引起Lyme disease吗 未知 和结论关联度低