OCT 1991, LR2, #16 (Please help!) Why is this answer correct?

LSAT Determined

Hello,

I chose E and can't really understand why it is wrong whereas C is correct. Can someone please break down the logic or reasoning behind this argument? Thanks in advance

nye8870

Hopefully we are talking about the same question PT2/Section 4/#16 (Weaken). At first read of this “sciency” stimulus, I tried to recall high school chemistry class. Then I imagined the flask inside an airtight chamber.. yadda yadda. But I sort of stopped myself and thought, “LSAT won’t use language or topics that general public couldn’t easily analyze for logical reasoning purposes.” So, the experimenters use “a measurable amount of helium-4 gas found in the air of the –chamber-” as evidence (Premise) for their conclusion that “fusion had been achieved.” I looked for an answer that leaves the premise intact as well as the conclusion but implies a reason the premise (while true) does not support the conclusion. This is what answer choice (C) does. Even though the amount of Helium-4 was measurable, the amount is the same as you might find in ordinary air. If this is the case, then measuring this level of Helium-4 is no reason to conclude “fusion” occurred. (E) May be a true fact in the real world. Who knows? But the stim never contemplates heat at all, so to assert one thing or another about heat becomes irrelevant to the argument. (A) So there are other gasses…(Naturally!) But we are concerned about Helium [Eliminate] (B) Other by products from fusion…Great! Measure those then! But our argument is turning on Helium so [Eliminate] (D) The stim states they found a “measurable” amount…When did they measure? Right after? Who knows? Did the experimenters wait too long and the higher concentration of Helium-4 broke down? We are not given enough info to weaken the experimenters’ conclusion with this one.