Neuroscientists are making progress in discovering more about the cause of AlzheimerтАЩs disease. AlzheimerтАЩs disease patients suffer from dementia and sever memory loss. Autopsies performed on such patients have revealed the presence of brain lesions caused by abnormal protein deposits. Similar deposits are also found in the brains of elderly patients who do not suffer from AlzheimerтАЩs disease. It follows that everyone who lives long enough will eventually develop AlzheimerтАЩs disease.

Which one of the following statements, if true, most seriously undermines the conclusion that everyone who lives long enough will eventually develop AlzheimerтАЩs disease?

(A) The lesions found in the brains of non-AlzheimerтАЩs disease patients are far less extensive than those found in the brains of AlzheimerтАЩs disease patients.

(B) The developing brain produces a greater number of cells than it will ever use. The extra cells are later destroyed by what biologists call тАЬprogrammed cell death.тАЭ

(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.

(D) Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.

(E) Though most AlzheimerтАЩs disease patients develop the disease when they are in their late fifties to early seventies, the frequency of patients who develop the disease in their forties is on the rise.


Answers with explanation!

I would go with D.

The contenders are C and D.

C) if the procedure for autopsy is not refined then it is possible that many patients not yet detected as having protien deposits might later be found to have such deposits if the procedure is refined. This in a way supports the conclusion. The argument links protien deposits to Alzheimers disease.

D) is direct hit in the sense that if some people do not have a chemical to help protien deposits to case brain lesions then one cannot say for sure that everyone will develop alzheimer's disease.