这题怎么会是E呢？

frankzhiwei

The milk of many mammals contains cannabinoids, substances that are known to stimulate certain receptors in the brain. To investigate the function of cannabinoids, researchers injected newborn mice with a chemical that is known to block cannabinoides from reaching their receptors in the brain. The injected mice showed far less interest in feeding than normal newborn mice do. Therefore, cannabinoids probably function to stimulate the appetite.

Which of the following is an assumption on which the argument depends?

A.Newborn mice do not normally ingest any substance other than theirmothers’ milk.

B.Cannabinoids are the only substances in mammals’ milk that stimulate the appetite.

C.The mothers of newborn mice do not normally make any effort to encourage their babies to feed.

D.The milk of mammals would be less nutritious if it did not contain cannabinoids.

E.The chemical that blocks cannabinoids from stimulating their brain receptors does not independently inhibit the appetite.

求解释！那个东东是促进脑袋接收器，后来又发现促进食欲，那这个假设跟那两个有何关系呀？

candyb110

E 选项取非就是weaken了，如果那个chemical 物质会抑制appetite的话，那么cannabinoids 抑制appetite的结论就不一定能从实验的结果中的得出了，因为可能是chemical的作用和cannabinoids无关