OG-134

puccamummy

134. Caterpillars of all species produce an identical hormone called "juvenile hormone" that maintains feeding
behavior. Only when a caterpillar has grown to the right size for pupation to take place does a special enzyme
halt the production of juvenile hormone. This enzyme can be synthesized and will, on being ingested by
immature caterpillars, kill them by stopping them from feeding.
Which of the following, if true, most strongly supports the view that it would not be advisable to try to
eradicate agricultural pests that go through a caterpillar stage by spraying croplands with the enzyme
mentioned above?
(A) Most species of caterpillar are subject to some natural predation.
(B) Many agricultural pests do not go through a caterpillar stage.
(C) Many agriculturally beneficial insects go through a caterpillar stage.
(D) Since caterpillars of different species emerge at different times, several sprayings would be necessary.
(E) Although the enzyme has been synthesized in the laboratory, no large-scale production facilities exist as
yet.

为什么B不对呢？

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重复发贴占用空间太不好意思了！

[此贴子已经被作者于2005-11-7 16:27:31编辑过]