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 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.

答案:C 但我怎么连题都读不懂啊，那位能帮忙解释一下thanks

生词太多了，我也不是学生物的，也懒得查，就用英文代替了
lyme disease是通过deer ticks 将一种病毒传染给人的。 deer ticks在laval阶段吃感染

的白足鼠而携带这种病毒。然而有一些物种--deer ticks 在laval阶段的食物--却不能成

为这种病毒的寄主。所以如果这种物种增加，ticks携带病毒，人接触lyme疾病的几率就会

下降。所以如果deer ticks在laval 阶段只feed一次，会加强这种下降。

我想larvae是deer ticks在laval阶段的一个特有名词吧。。。猜的