天山7－13 弱若的问题

mywaymydream

Q13:
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 whitefooted
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?
A. Ticks do not suffer any adverse consequences from carrying the bacterium that
causes Lyme disease in humans.
B. There are no known cases of a human’s contracting Lyme disease through contact
with white-footed mice.
C. A deer tick feeds only once while in the larval stage.
D. A single host animal can be the source of bacteria for many tick larvae.
E. None of the other species on which deer tick larvae feed harbor other bacteria that
ticks transmit to humans.

看了网上的讨论，对于C选择，哪位能给讲解下吗，如果是要WEAKEN会怎样。

好像这种题目的思路不是很清楚，一遇到这种生物方面的问题就晕，阅读不好，加上思路不清。谢谢

[此贴子已经被作者于2006-8-8 10:52:25编辑过]

mymengming

文章的大题思路是

DT的幼虫吃WM(又传染的)和其他的(没有传染)的东东,然后人得病(L病)从DT上

如果其他的(没有传染)增加,就会使DT和人传染上细菌并得L病得就少了

很完美的推理,问加强

因为完美,所以加强只能是1,外力  2,自身没有发现得性质

这里C就是2了,因为只吃一次,所以传染得就少了,因为如果吃两次得话,DT咬了口没有病得,感觉不好吃,就去吃有病的WM,这样就算没病的多了也没有用

所以是支持

mywaymydream

唉，我得阅读太差了，读了半天也读不懂。

祝你取得好成绩。

3bao

答案是C

A deer tick feeds only once while in the larval stage

当他在larval stage只吃一次饭时，other species数量增多，他才有可能吃到other species

如果他吃很多顿饭就不一定吃什么了，哈哈，饥不择食就是这个道理~~