#9 - Two lakes in the Pawpaw mountains, Quapaw

[Albertlyu]

Hi ronibass,
Answer A is incorrect because it would require quite a bit more information to determine its relevance. For example it notes that Lake H is in an area highly susceptible to acid rain, but we don't know whether Lake Q is similarly situated. We would also need to know whether acid rain had anything to do with fish reproduction/re-population. Without knowing those things we can't be sure whether Answer A would weaken the argument.
Hope that helps!
-Malila

thanks, Malila, I got A, now I can see why B is much better at weakening the argument(again I need to deal with my careless reading habit). But from previous cases, I got the impression that with str/weaken questions, so long as the answer choice offers a reasonable alternative explanation, it can be a strengthener or weakener, even it requires an additional assumption. Please may I ask if this understanding is absolutely wrong in any way shape or form or can be applicable sometimes? thanks.

[Robert Carroll]

Albert,

An answer that weakens in any way is fine. As Malila points out, answer choice (A) does not weaken, because we need more information than it even provides to assess its relevance. The "additional assumption" we have to make here could go any way - a way that weakens, a way that strengthens, or a way that has no effect. It's not as if the "additional assumption" we need to make the answer here relevant is straightforward in that there is only one class of such assumptions, all of them having the same effect on the argument. With an equally reasonable additional assumption, we can make answer choice (A) strengthen the argument. So it does nothing on its own. Nothing in the answer tells us that Quapaw doesn't suffer acid rain, or that it does, so we don't even know if this is a difference between the lakes, or a similarity. Even if we knew that, knowing how this affects the argument might require even more assumptions, the thrust of which can't be predicted in advance.

Robert Carroll

[Albertlyu]

thank you, Robert for your explanation, I got it now.

Regards

Albert