一题CR JJ题，与答案看法不同

题目如下：

36、GWD29-40

Mice that have been given morphine are very likely to develop blood poisoning because bacteria that normally reside in the intestine typically respond to morphine by migrating into the bloodstream.  However, when mice are given both morphine and the new drug naltrexone, blood poisoning is much less frequent, although it does still occur.  These results provide support for researchers’ prediction that naltrexone will turn out to be toxic to certain types of bacteria.

Which of the following, if discovered to be true, would most seriously weaken the support for the researchers’ prediction?

1. After being administered to mice, naltrexone does not pass from the bloodstream into the intestine.

2. Naltrexone inhibits morphine from triggering the migration of intestinal bacteria into the bloodstream.

3. Mice that have been given naltrexone but not morphine have no greater risk of developing blood poisoning than do mice that have not been given either substance.

4. The increased risk of blood poisoning is not the only harmful effect on mice of being given morphine.

5. Conditions other than the presence of intestinal bacteria in the bloodstream can cause blood poisoning in mice.

(答案: C, 给或者不给naltrexone，blood poisoning发病率不变，推出结论中naltrexone导致中毒说法错)

我的意见：应该选B，N通过抑制M的作用来减轻blood poisoning,正好是找他因的weaken. 而C，是说打了N的不比没打的得blood poisoning风险大,

那么打了N而不打M，如果N toxic to bacteria的话，也是杀掉肠子里的bacteria,跟blood poisoning无关;对于两者都不打的情况是差不多的

我以为题目需要weaken的结论是 Naltrexone 可以单独拿出来作为广谱抗生素使用( These results provide support for researchers’ prediction that naltrexone will turn out to be toxic to certain types of bacteria.) b选项  还是在讲 Naltrexone 与吗啡的作用关系