Thousands of people have tonsillectomies every year and all live norma

Thousands of people have tonsillectomies every year and all live normal lives after the operation. We can conclude, from this observation, that the tonsils have no function in the body.

The argument would be most weakened by which of the following, if it were true?

A. People live normal lives after appendectomies but the appendix is known to be part of the digestive system.
B. Another part of the body can take over the function of the tonsils if they are removed.
C. The tonsils have been shown to have a vital role to play in the physiology of laboratory rabbits and guinea pigs.
D. The human tonsil develops as part of the immune system, a system of vital importance in defense against disease.
E. Tonsillectomies are performed only when the tonsils become seriously infected.

Nothing about B tells us that the tonsils have a function. D does that, it clearly states that they are part of the immune system. Are we to infer that the immune system develops parts that serve no function?

In order to weaken we need to show that Tonsils has a function in the body.
That's what B does.
D on the other hand says Tonsils is a part of immune system but doesn't say if it has a function.
Hence B is the right choice!

Thousands of people have tonsillectomies every year and all live normal lives after the operation. We can conclude, from this observation, that the tonsils have no function in the body.

The argument would be most weakened by which of the following, if it were true?

A. People live normal lives after appendectomies but the appendix is known to be part of the digestive system. (out of scope)
B. Another part of the body can take over the function of the tonsils if they are removed. (keep)
C. The tonsils have been shown to have a vital role to play in the physiology of laboratory rabbits and guinea pigs. (out of scope)
D. The human tonsil develops as part of the immune system, a system of vital importance in defense against disease. (keep)
E. Tonsillectomies are performed only when the tonsils become seriously infected. (out of scope)

Between B and D, B tells us exactly that tonsils have a vital part, but its function is taken over by other body part. D tells us that tonsil develops as part of immune system, but does not tell us whether it plays any vital role or not.

Hence, B is the best choice.

B is the answer as D shows no function of the organ.
Nevertheless, this question still sounds like an inference question. Anyway, this is still a strengthen question, and B is the answer.

Please explain what's wrong with D.

D. The human tonsil develops as part of the immune system, a system of vital importance in defense against disease.

Here,tonsil is a part of the immune system,which is very important for body.But without further information we can't say immune system's tonsil is important for our body.

So,Answer choice D does not necessarily weakened the argument/conclusion,Thus incorrect

Thanks.

Has to be B, the key is " all live normal lives after the operation".

- All live normal lives after the operation only because some other part of the body took over the function of tonsils.
- if no other part took over the functionality, people won't be living a normal life => implies => tonsils has some function in the body