A drug that is highly effective in treating many types of in

[H]

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.

============================================
Premise: the effective drug can only be obtained from the bark of the ibora
Premise: ibora is rare in the wild
Premise: bark of 5000 ibora=1KG of such drug
Conclusion: continued production of the drug=>ibora's extinction
============================================
I eliminated A, B and C.
I chose E because I thought that if ibora is in inaccessible places, where no one can reaches, then the production of such drug will completely halt. And then, it won't be extinct. How come my reasoning is wrong?

I thought that one way to weaken the argument is stating that the if condition (which is "production of the drug continues") is invalid.

Thanks in advance.

[H]

Is it a rule that I am not supposed to attack the "cause" stated in the conclusion?

[rfernandez]

The conclusion, which you correctly identifies, concerns itself mainly with the extinction of the ibora tree: if production of the drug continues --> the ibora tree will become extinct.

Notice how D speaks directly to this issue. If the tree can, in fact, be grown from cultivation then extinction will not be an inevitable outcome. This severely weakens the extinction argument.

The rationale you give for E assumes that the inaccessibility of the ibora will eventually stop production, and so the tree won't become extinct. A better way to weigh E is to consider that even if the trees are found only in inaccessible places, the conclusion would still hold: IF production of the drug continues, THEN the tree would still become extinct. Choice E in no way addresses the extinction issue directly. Surely your line of reasoning makes sense, but it's too complicated a tale to be a typical GMAT correct answer. I might give E a "slightly weakens" while D is a "severely weakens."

[H]

Thanks.

[StaceyKoprince]

we're happy to help!

[AbigailS228]

I had the same issue as the person above; however the GMAT explanation does not completely explain it for me.

I think it is E because if it is inaccessible then how can the production of the drug lead to its extinction? It may become extinct on it's own, but it surely will not become extinct BC of the production of the drug (since they cannot access these tries).

I understand how D weakens the argument; however, even if it can be grown under cultivation, what if it cannot be replenished fast enough (you need 5,000 trees for one kg and trees take a LONG time to grow). I think D would take a lot more outside justification, like they can cultivate it quickly enough, than E does.

[RonPurewal]

I think it is E because if it is inaccessible then how can the production of the drug lead to its extinction? It may become extinct on it's own, but it surely will not become extinct BC of the production of the drug (since they cannot access these tries).

For "continued production" to occur, the pharma people have to get the ibora.
If it's in "largely inaccessible" places, then, tough nuts--it'll take more effort to get it (and the drug will consequently be super-expensive). But that doesn't change the fact that continued production = get more tree bark. Even if the only iboras left are on the moon.

[RonPurewal]

I understand how D weakens the argument; however, even if it can be grown under cultivation, what if

Immediately truncate ANY thought process that contains "what if", "might", "could", etc.
Quit right there. Don't even finish the sentence; it's a non-argument.
You can't make up random possibilities and then try to argue from them.

Basically, if you come at these things with "What if xxxx?", then whomever you're debating can just come back at you with "What if not xxxx?" And, of course, there'd be no reason to take one of these over the other.

[RonPurewal]

In fact, if "What if...?" were a valid way to strengthen/weaken an argument, it would be possible to make almost any statement strengthen or weaken almost any argument. You could just keep making up hypotheticals until the two ideas became connected to each other.
Not how it works.

Instead, if your thought process contains things like "It's almost certainly true that _____", THEN you keep going with it.