这题我选C,他因。
以下是引用thinkpad在2003-7-17 14:42:00的发言:2. 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 immatune 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 agricultral pests that go through a caterpillar state 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 state. c) Many agriculturally beneficial insects go through a caterpillar state. 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 facilites exist as yet. 我想选e,同样和新东方答案不同,请大家说说我这道题又是哪里想的不对? [此贴子已经被作者于2003-7-17 14:45:23编辑过] |