24套GWD第13个逻辑题目

从容自适

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?  

 

1. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
2. There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice.
3. A deer tick feeds only once while in the larval stage.

4. A single host animal can be the source of bacteria for many tick larvae.
5. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

牛牛们帮帮想想为什么选C呢,我觉得似乎也有点牵强...

shaan

应该是C啊，因为这种TICK只能寄养一次，在幼虫时期（就是说他不会从这个动物身上跑到那个动物身上），那么显然如果其他物种增加了，寄养在其他物种的tick就多了，而他又不可能二次寄养到有细菌的老鼠身上，那么就是传染这种细菌的几率减少了。D就是和他相反的说法，如果说削弱，那么D就是另一个答案。

[此贴子已经被作者于2008-5-14 18:51:07编辑过]