Ibora

sankruth · Posted: Thu Jan 24, 2008 12:44 pm Post subject: Ibora

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.

Can someone please explain what is wrong with D. The Oa is E

Stuart Kovinsky · Posted: Thu Jan 24, 2008 1:45 pm Post subject:

Not sure where you got those answers from, but your choice is definitely the correct one (and the answer you've stated as correct is defintely wrong).

sankruth · Posted: Thu Jan 24, 2008 2:58 pm Post subject:

Its from the 1000SC set. I guess the OA must be wrong then!

sibbineni · Posted: Thu Jan 24, 2008 5:43 pm Post subject:

could you please explain your answer

simplyjat · Posted: Thu Jan 24, 2008 11:08 pm Post subject:

D is the correct answer, look in the question stem
"a tree that is quite rare in the wild".
Here the argument makes an assumption that the tree can only grow in wild and not by cultivation.

There are other loop-holes in in argument, such as removing the bark destroys the tree... but they are not mentioned in the answer choices.

E is not the correct answer, as it strengthens on the the premises "a tree that is quite rare in the wild"...

Stuart Kovinsky · Posted: Fri Jan 25, 2008 7:06 am Post subject:

To make the leap from "it takes a lot of trees to make the drug" to "the tree will become extinct", the author has to be assuming that the supply of trees is finite.

To weaken the argument, we look for an alternative to this assumption. Any answer choice that suggests that the supply of trees isn't as limited as the author says will weaken the conclusion.

(D) says that we can grow the tree at tree farms (or greenhouses, or whatever). If we can grow the tree ourselves without touching the trees in the wild, then there's no reason why the tree should become extinct.

Choose (D).

sibbineni · Posted: Sat Jan 26, 2008 5:01 am Post subject:

thanks stuart