100.
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 by feeding on infected white-footed mice.
However, certain other species on which the
larvae feed do not harbor the bacterium.
If the population of these other species were increased, more of the
larvae would be feeding on uninfected hosts, so the number of ticks acquiring
the bacterium would likely decline.
Which of
the following would it be most important to ascertain in evaluating the
argument?
A.
Whether populations of the other species on which deer tick larvae feed are
found only in areas also inhabited by white-footed mice B.
Whether the size of the deer tick population is currently limited by the
availability of animals for the tick's larval stage to feed on C.
Whether the infected deer tick population could be controlled by increasing the
number of animals that prey on white-footed mice D.
Whether deer ticks that were not infected as larvae can become infected as
adults by feeding on deer on which infected deer ticks have fed
E.
Whether the other species on which deer tick larvae feed harbor any other
bacteria that ticks transmit to humans
正确答案是B。
第一次做的时候没有选出答案，觉得选项都不能很有效的evaluate argument。
请大家看看我的推理思路是否有问题，总觉得很别扭。 因为other species不会携带那种bacterium，所以增加other species的数量，deer ticks被感染的数量就有可能减少。
B选项里，如果deer tick的数量目前受其生长初期进食的动物数量限制，那增加other species的数量，就会导致deer
tick数量的增加，从而更多的deer tick以other species为食，因此受感染的数量减少，support结论；反之如果不受限制，既使增加other species的数量，deer tick不一定会增多，受感染的deer tick数量也不一定会减少，weaken结论。 | 
