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标题: 急问GWD6-13，小女子愚钝，请不吝赐教 [打印本页]

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作者: christy42728    时间: 2007-11-17 16:14
标题: 急问GWD6-13，小女子愚钝，请不吝赐教

因为没人回答，很着急所以另开了一帖，如果有答案了就删了吧，不想造成重复，这道题目应该看懂了，前提１）L这种病是被感染了B的T传染给人的。２）T是因为在LS 吃了被感染的M 3)但是喂给T的其他东西没有被感染

结论：如果给T吃的没有被感染的其他东西多了－〉T被感染的机会就会减少－〉那种病传给人就会减少

无论如何也不明白这跟T在LS哪吃几次有什么关系

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.

The given correct answer is C.

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作者: racing78    时间: 2007-11-17 16:31

本題看法：

DT會帶細菌，這種細菌會使人生病，通常DT是在幼蟲時期依附白腳老鼠覓食時帶有這種細菌

但是如果DT長在其他種類老鼠身上不會帶細菌,依題目說法關鍵就在於老鼠種類

因此如果推論當其他種老鼠多時，假如DT在幼蟲時只能feed一次，則feed on 白老鼠機率

就會下降(機率問題)，故可以支持結論是疾病數下降.

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作者: christy42728    时间: 2007-11-17 16:37
明白了，谢谢

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