LSAT PrepTest 43 Section 2 Question 2 Explanation | Logical Reasoning

I didn't write the following blog post. It was already on the blog when I took over the URL. The following blog post may contain mistakes. -Steve

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This Logical Reasoning question is from the June 2004 LSAT.

As usual, let's make a chain of phrases to show how the argument progresses (this can be through underlining key words, once you get more experience):

Earth is a living organism --> has organism's characteristics --> doesn't breathe, but neither do insects

We see the point of this argument is to argue that the earth's a living organism. To support this view, the speaker says the earth has certain characteristics (like a metabolism) in common with other living organisms. Finally, the speaker says that the earth doesn't literally breathe, but that insects don't either.

The implication is clear...insects are obviously organisms, and they don't breathe, so the earth not literally breathing doesn't mean it isn't an organism. This is just another part of the speaker's argument that the earth's an organism.

So, we can pre-phrase a role of the speaker's point that the earth doesn't literally breathe...something like "to show that although the earth doesn't literally breathe, that doesn't mean it's not a living organism." We notice immediately that choice A fits well, since it says that the role is to rule out a reason for not calling the earth an organism, which is the main point of our pre-phrase. Let's quickly go through the other choices:

A) Correct.

B) The opposite of what we want. The argument is clearly about saying the earth is an organism, as our chain tells us. Obviously, no part of the argument is going to be saying the opposite! Also, our pre-phrase says that part of the argument is meant to support the view of earth as an organism.

C) Beyond the scope of that part of the argument. It's talking about respiration and doesn't mention metabolism. Since it doesn't address that, metabolism can't be the point of that part of the argument.

D) The opposite of what we want. The argument makes clear that the insect is an organism. That's the reason for bringing insects up, since they show that breathing isn't necessary to be an organism by their status as non-breathing organisms.

E) Way beyond the scope of the argument. Insects obviously aren't what earth is composed of.

Remember:

1) Make a chain of phrases (by underlining, once you get more experienced) and pre-phrase an answer (when there's a definite one, as there is here) to save time slogging through wrong answers.

2) Eliminate answer choices that are beyond the scope of the part of the argument the question's asking about or the argument as a whole, and make sure to eliminate answer choices that say the opposite of the kind of answer we're looking for. These two very simple categories can eliminate almost all wrong answer choices.