标题: 各位大侠来救命啊~~关于caterpillar与spray enzyme的题，OG11版第117题 [打印本页] 作者: annieying126 时间: 2009-12-3 20:27 标题: 各位大侠来救命啊~~关于caterpillar与spray enzyme的题，OG11版第117题 Caterpillars of allspecies 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.（C） (E) Although the enzyme has been synthesized in the laboratory, no large-scale production facilities exist as yet.