LSAT Explanation PT 35, S4, Q10: A recent study suggests that Alzheimer's

LSAT Question Stem

Which one of the following statements, if true, would most strengthen the scientist's hypothesis that Alzheimer's disease is caused by a virus? 

Logical Reasoning Question Type

This is a Strengthen question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

In this passage, the argument is as follows:

Premise: A study found that when blood from Alzheimer's patients was injected into rats, the rats developed symptoms of Creutzfeldt-Jakob (C-J) disease.

Premise: C-J disease is caused by a virus.

Conclusion: Alzheimer's disease might be caused by a virus.

The structure of the argument is based on the connection between Alzheimer's disease and C-J disease. The conclusion is drawn from the fact that C-J disease, which is caused by a virus, is exhibited in rats after they receive blood from Alzheimer's patients. The argument assumes that there is a connection between Alzheimer's and C-J disease.

An "Evaluate" question for this argument would be: "Is there a strong connection between Alzheimer's disease and C-J disease?"

Now, let's discuss the question type and the answer choices. This is a Strengthen question, which asks us to identify the statement that, if true, would most strengthen the scientist's hypothesis that Alzheimer's disease is caused by a virus.

a) This answer choice, if true, would actually weaken the argument. If Alzheimer's disease in rats is not caused by a virus, it would make it less likely that Alzheimer's disease in humans is caused by a virus.

b) This answer choice brings up a difference between C-J and Alzheimer's, weakening the connection between them. It doesn't help to strengthen the argument.

c) The effect of the C-J virus on humans is not relevant to the connection between C-J and Alzheimer's. This answer choice doesn't help to strengthen the argument.

d) Correct answer. If the symptoms of C-J and Alzheimer's are different manifestations of the same disease, it strengthens the connection between the two diseases. This makes it more likely that Alzheimer's is caused by a virus, just like C-J disease.

e) This answer choice, if true, would show that blood transfusions alone don't cause C-J disease. However, it doesn't provide any support for the connection between Alzheimer's and C-J disease. It is consistent with C-J disease being caused by a virus or not, and Alzheimer's disease being caused by a virus or not. Thus, it doesn't help to strengthen the argument.

In conclusion, answer choice D is the correct answer, as it strengthens the connection between Alzheimer's and C-J disease, making it more likely that Alzheimer's is caused by a virus.