Critical Reasoning

Dear Friends,

I was having problems in answering the following question.

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?

A. After being administered to mice, naltrexone does not pass from the bloodstream into the intestine.
B. Naltrexone inhibits morphine from triggering the migration of intestinal bacteria into the bloodstream.
C. 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.
D. The increased risk of blood poisoning is not the only harmful effect on mice of being given morphine.
E. Conditions other than the presence of intestinal bacteria in the bloodstream can cause blood poisoning in mice.


Please help.

OA after some discussions.

Regards
Deano.

Choice B) seems to the most logical answer: the objective is to prove that naltrexone (N) is not harmful to bacteria. If all N does is inhibit Morphine (M) from triggering the bacteria, it does not harm the bacteria directly. So, it's not harmful to the bacteria, it's simply not helpful to it.

Should be C, meaning that Naltrexone is not toxic.

Please provide OA and OE.

Thanks.

Mice+ Nanx is same as Mice(without either of them)

That means Nanx has no effect on bacteria

Choice is (C)

My answer is A since this is a Weaken the conclusion' question

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?

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


If Naltrexone can't go to the intestine, how it can reduce the bactaria reside there? Correct! It weakens the conclusion.

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

This simply repeats the conclusion. or Strengthen the conclusion. Incorrect.

C. 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.

It dosen't much weaken the conclusion. Not relevant.

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

Irrevant

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

Irrevant