sperinko wrote:
A drug that is highly effective in treating many types of infection can, at present, be obtained only from the bark of the ibora, a tree that is quite rare in the wild. It takes the bark of 5,000 trees to make one kilogram of the drug. It follows, therefore, that continued production of the drug must inevitably lead to the ibora's extinction.
Which of the following, if true, most seriously weakens the argument above?
(A) The drug made from ibora bark is dispensed to doctors from a central authority.
(B) The drug made from ibora bark is expensive to produce.
(C) The leaves of the ibora are used in a number of medical products.
(D) The ibora can be propagated from cuttings and grown under cultivation.
(E) The ibora generally grows in largely inaccessible places.
The conclusion of this particular passage is the last line.
It follows, therefore, that continued production of the drug must inevitably lead to the ibora's extinction.A.
Incorrect. How the drug is made available to doctors will not affect the conclusion as it talks about the "continued production". This might perhaps result in the extinction happening a bit later than if the drug was made available otherwise, but that doesn't mean that it will never lead to ibora's extinction.
B.
Incorrect. Expense is irrelevant to the conclusion.
C.
Incorrect. The argument talks about the production of the drug which is made from the bark of the tree. The leaves of ibora are irrelevant to the conclusion.
D.
Correct. This gives us a reason to believe why the Ibora might not be extinct despite the continued production of the drug.
E.
Incorrect. Just because Ibora generally grows in places that are largely inaccessible doesn't mean it can't be extinct. Moon, for some, might be a largely inaccessible place but people have still managed to reach that. The top of the Mount Everest is also an inaccessible place, but people have reached that too. So, really this does not affect our conclusion as much.