Robust crops not only withstand insect attacks more successfully t

Question

Robust crops not only withstand insect attacks more successfully than other crops, they are also less likely to be attacked in the first place, since insects tend to feed on weaker plants. Killing insects with pesticides does not address the underlying problem of inherent vulnerability to damage caused by insect attacks. Thus,a better way to reduce the vulnerability of agricultural crops to insect pest damage is to grow those crops in good soil—soil with adequate nutrients, organic matter, and microbial activity.

Which one of the following is an assumption on which the argument depends?

(A) The application of nutrients and organic matter to farmland improves the soil’s microbial activity.
(B) Insects never attack crops grown in soil containing adequate nutrients, organic matter, and microbial activity.
(C) The application of pesticides to weak crops fails to reduce the extent to which they are damaged by insect pests.
(D) Crops that are grown in good soil tend to be more robust than other crops.
(E) Growing crops without the use of pesticides generally produces less robust plants than when pesticides are used.

Sanjay7392 · Answer

Evidence -->Robust plants wont be attacked by pests.

Conclusion---> Concentrate on making soil stronger with nutrients, org matter, etc.

Evidence + Missing information = Conclusion

Prethink for missing information ---> Making soil stronger with nutrients, organic matter, etc. will make plants growing there robust.

(A) The application of nutrients and organic matter to farmland improves the soil’s microbial activity. -  This doesn't relate to making plants robust - Incorrect 
(B) Insects never attack crops grown in soil containing adequate nutrients, organic matter, and microbial activity. -  This doesnt take into consideration the evidence part of the argument. - Incorrect 
(C) The application of pesticides to weak crops fails to reduce the extent to which they are damaged by insect pests. -  Out of Scope - We need to concentrate on the benefits of making soil healthy instead of concentrating on weak crops. 
(D) Crops that are grown in good soil tend to be more robust than other crops. -  Exact point as mentioned in prethink. - Correct 
(E) Growing crops without the use of pesticides generally produces less robust plants than when pesticides are used. -  Same as option C - Incorrect

dcummins · Answer

Conclusion: Grow crops in good soil to reduce vulnerability of crops to insect damage since insects prey on less robust crops.

D must be true for the argument to be true.

Try negating

Crops that are grown in good soil do not tend to be more robust than others

Then crops grown in good soil will likely have the same vulnerability as other weaker crops.

Let's look at negating E:

It is NOT the case that Growing crops without the use of pesticides generally produces less robust plants than when pesticides are used.

Then it really doesn't add much to our conclusion. Pesticides are only discussed in relation to warding off insects as a result of less robust crops.

panopticon · Answer

Robust crops not only withstand insect attacks more successfully than other crops, they are also less likely to be attacked in the first place, since insects tend to feed on weaker plants. Killing insects with pesticides does not address the underlying problem of inherent vulnerability to damage caused by insect attacks. Thus,a better way to reduce the vulnerability of agricultural crops to insect pest damage is to grow those crops in good soil—soil with adequate nutrients, organic matter, and microbial activity.

Which one of the following is an assumption on which the argument depends?

(A) The application of nutrients and organic matter to farmland improves the soil’s microbial activity.
 Nowhere does it say that we require microbial activity on its own to reduce vulnerability of agricultural crops

(B) Insects never attack crops grown in soil containing adequate nutrients, organic matter, and microbial activity.
 There are two clear issues with this one: 1. the use of "never" - the stem is clearly focused on reducing attacks, not completely eliminating them. 2. we're not looking to prove that insects will never attack crops that are grown in a certain type of soil, we're looking to prove if a certain type of soil can actually make crops grow more robust; this, in turn, may allow crops to be more effective at defending against insects attacks.
 
(C) The application of pesticides to weak crops fails to reduce the extent to which they are damaged by insect pests.
 This is not stated anywhere in the question stem.

(D) Crops that are grown in good soil tend to be more robust than other crops.
 The argument states that applying pesticides to weak crops is akin to treating pain for a condition and not the underlying disease. The argument also suggests that to reduce attacks from insect pest, the crops should be grown in "soil with adequate nutrients, organic matter, and microbial activity". Thus, we should assume that growing the crops in such soil may make the crops more robust, and in turn, more resistant to attacks from insects.. BINGO.

(E) Growing crops without the use of pesticides generally produces less robust plants than when pesticides are used.
 Nowhere does it state that crops are even grown with pesticides.

akela · Answer

Manhattanprep explanation

First, 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.

VerbalBot · Answer

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Robust crops not only withstand insect attacks more successfully t

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