求教，GWD-TN-16，第40题。

Plantings of cotton bioengineered to produce its own insecticide against bollworms, a major cause of crop failure, sustained little bollworm damage until this year.  This year the plantings are being seriously damaged by bollworms.  Bollworms, however, are not necessarily developing resistance to the cotton’s insecticide.  Bollworms breed on corn, and last year more corn than usual was planted throughout cotton-growing regions.  So it is likely that the cotton is simply being overwhelmed by corn-bred bollworms.

In evaluating the argument, which of the following would be most useful to establish?

1. Whether corn could be bioengineered to produce the insecticide

2. Whether plantings of cotton that does not produce the insecticide are suffering unusually extensive damage from bollworms this year

3. Whether other crops that have been bioengineered to produce their own insecticide successfully resist the pests against which the insecticide was to protect them

4. Whether plantings of bioengineered cotton are frequently damaged by insect pests other than bollworms

5. Whether there are insecticides that can be used against bollworms that have developed resistance to the insecticide produced by the bioengineered cotton

答案是B。

这道题是什么逻辑？一直没想明白。

如果说B答yes是支持结论，答no是反对结论的话。因为虫多了棉花就damage了，难道说棉花的杀虫剂对大量的虫就没有效果了？只在虫少的时候有效果。这好像有点奇怪啊。

但是如果答no支持结论，答yes反对结论的话。我就更想不明白了。

求高人指教。

刚搜到了以前讨论的帖子，好像确实是这样。

可是这不是很没道理么，为什么有抗虫性的棉花在虫变多了就不管用了，那这个抗虫性也太挫了吧。。。。