Q23 - Robust crops not only withstand

[bbirdwell]

Also notice how broad the language in the question is. "more successfully". "less likely". "tend to". Those are additional clues for us to avoid extreme language in necessary assumption questions.

Nice analysis!

Here's what my process looked like on this one:

First I check out the argument.
robust --> withstand insect and less likely to be attacked (b/c insects feed on weaklings)

pesticides don't reduce vulnerability

therefore: better way to reduce vulnerability = good soil

At this point, I can't really articulate any particular assumption or gap, but I note that the key concept in the conclusion is "good soil," which likely have to be part of the answer, and the other thing that sticks out is the idea of "robustness." The conclusion is about crops in general, while one of the two premises is only about robust crops.

Hmm. Now I'll go to the choices and look for easy eliminations.

(A) not even close

(B) close, but "never" is no good here. I can verify this by negating: SOMETIMES, insects attack crops grown in good soil. This doesn't really invalidate the reasoning or the conclusion. Good soil could still be "better" even though insects sometimes attack. Nice try, LSAT. Eliminate!

(C) ballpark elimination without getting too involved in thinking about it -- the restriction to "weak" crops is suspect, as is the lack of "good soil."

(D) hmm. It's got "good soil" and "robust." Lemme think about it... I dunno. What if I negate it? Crops in good soil NEVER more robust. Well, considering the reasoning here (robust crops are better), this is a good match. If good soil doesn't make the crops robust, we are left with no evidence in the argument to support the conclusion. All we know is that pesticides don't work, and we've no support at all for the idea that good soil is better somehow. This must be the answer. Quick check for (E).

(E) On the one hand, this one could weaken, if we assume that the "good soil" crops aren't using pesticides. But we don't know whether that's true. In order to be relevant, my answer needs to address "good soil" somehow. This choice compares pesticides vs no pesticide, but never pesticide vs good soil. Eliminate.

Therefore, by approaching the LSAT like it's the LSAT, utilizing negation tests for necessary assumption questions and playing the elimination game, I get this question right.

In the heat of the moment, under pressure, I may not be 100% certain exactly how (D) fits into the argument, but I know that the others are definitely NOT necessary assumptions, and I know (D) is relevant to the reasoning. This is enough for me to choose with confidence and move on.


#officialexplanation

[vaikall]

I eliminated A, C, and E and was debating between B and D.
I understand that B is unnecessarily strong in its stance but doesn't it make the argument more strong than D does?

[aquyenl]

B says that insects never attack. That is too strong as the question asks us to just find what is necessary. If b said instead that insects were less likely to attack those crops then that would work as our answer.

Also notice how broad the language in the question is. "more successfully". "less likely". "tend to". Those are additional clues for us to avoid extreme language in necessary assumption questions.

B is sufficient for the argument to work but it is not necessary for it to work.

[economienda]

I also got down to (B) and (D). I was able to eliminate (B) because it just says "soil" but in the stimulus, we're dealing with a specific type of soil: good soil. (B) was then ambiguous. (D) however did specify that we are dealing with good soil. I didn't even have to use the negation test.

[Puffy Pants]

I personally eliminated B quickly because I thought "never" was too extreme. Also when you consider that robust crops are not infallible to insect attacks "Robust crops (not) only withstand insect attacks more successfully...." I think that if they are robust their soil is better (which is the argument) so Robust crops do get attacked regardless of the soil they are in, they are just able to handle it it better since they are not as weak. So that would make B wrong.