PT60.S1.Q24 - mammals cannot digest cellulose

alkhatib683

http://7sage.com/lsat_explanations/lsat-60-section-1-question-24/
Okay, so perhaps I'm overthinking this, but here goes:


I put down (B) rather than (C) for the following reason: the stimulus indicates that the degree of immuno-effect is related to branching of the beta-glucans, but states that beta-glucan extracts from the shrooms have this effect (i.e. Whether b-g 's in general do is not stated). Thus, to say that b-g branching triggers immuno-effects in mammals (answer C) seems to overshoot what's in the passage, whereas (B), which only mentions that if extracts have an immuno-effect, then that shroom must be making b-g 's.

Tell me where i'm going wrong.

Thanks & all the best w/ practice,

Z

EuripidesFan

I believe B is, or approximates, the error of a mistaken reversal.

While it is true that "some" (line 3) mushrooms make use of this branching process to create beta-glucans that do slow, reverse or prevent cancerous growth (according to the stimulus).... can we logically infer that if an extract does this then it must definitely be capable of producing beta-glucans. All we know is that some mushrooms use branched polymers to achieve this effect... not that all mushrooms that achieve this effect must therefore be capable of making branched polymers.

And C, in my opinion, doesn't overshoot but is instead directly inferable from the 2nd and 3rd sentences. It is slightly confusing however on account of the referential phrasing: "antitumor activity" can be equated with "increasing-cell activity" because we are told as much in the last sentence that the method in which these beta-glucans work is "not by killing cancer cells directly but by increasing immune-cell activity". The 2nd sentence however says that this "antitumor activity" increases as the degree of branching increases.... thus we can conclude that immune-cell activity increases as the degree of branching of beta-glucans increases.

Hope that was helpful!

Angelica Pickles

Great explanation Euripides.
I would just add that if had the sufficient & necessary conditions flipped then it would be a contender.

alkhatib683

Thanks EuripidesFan