Farmer: Crops genetically engineered to produce toxins that enable

Question

Farmer: Crops genetically engineered to produce toxins that enable them to resist insect pests do not need to be sprayed with insecticides. Since excessive spraying of insecticides has harmed wildlife populations near croplands, using such genetically engineered crops more widely is likely to help wildlife populations to recover.

Which of the following is an assumption the farmer's argument requires?

(A) Use of the crops that have been genetically engineered to resist insect pests in place of crops that have been sprayed with insecticides will cause less harm to wildlife populations

(B) Wildlife populations that have been harmed by the excessive spraying of insecticides on croplands are likely to recover if the amount of insecticides sprayed on those croplands is reduced even slightly

(C) Crops that have been genetically engineered to resist insect pests are never sprayed with insecticides that harm wildlife populations

(D) Use of crops that have been genetically engineered to resist insect pests is no more costly to farmers than the use of insecticides on crops that are not genetically engineered

(E) If a wider use of certain crops that have been genetically engineered to resist insect pests is likely to help at least some wildlife populations to recover, it is likely to have that effect only because its use will prevent excessive and ineffective spraying of insecticides on croplands

AlexTheTrainer · Accepted Answer

This question is an excellent example of the importance of properly applying the negation test to assumption questions.

As a rule, answer choices should be negated in the easiest, most straightforward way possible.

The easiest, most straightforward way to negate (A) would be to change “will cause less harm” to “will cause more harm”. Doing so clearly kills the conclusion.

Please note that according to the strict standards of logic, the above negation is NOT accurate. Technically, negating “will cause less harm” results in “won’t necessarily cause less harm”. And this technically correct negation certainly does not kill the conclusion.

Because in logic, there’s no such thing as killing a conclusion. An argument is either valid (evidence/premises leading to a conclusion that must be true) or invalid (evidence/premises leading to a conclusion that does not have to be true).

Fortunately, for purposes of CR, no one has to worry about any of that nonsense. On the GMAT, when a straightforward negation of an answer choice kill the conclusion, that’s definitely the necessary assumption.

That all being said, there is a major exception to the idea of a straightforward negation, which can be found in (trap?) answer choice C.

A straightforward negation of C would result in “ALWAYS sprayed with insecticides”, which appears to cause a problem in the argument. However:

Always negate “some” and “sometimes” (and “many”) into “no”, “none”, etc. AND vice-versa. In the case of (C), “never” should be negated into “sometimes”.

Turning “never” into “sometimes” should seem to not affect the argument, especially since it discusses “excessive” insecticide spray.

Final note: occasionally, assumption answer choices will be phrased in if/then form. For example, “if x then y”.

The technical negation would be “even if x then not necessarily y”. But for CR purposes, the straightforward negation would be sufficient: “if x then not y.”

Fun times...

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Harsh9676 · Answer

I got the question wrong.

But I can guess why A is correct.

The Argument says that Excessive use of insecticides harm wild life, while choice C do not say anything about the quantity of insecticides used.

ShreyasJavahar · Answer

Don't quite see how A can be the answer. (A) says it causes the genetically modified crops cause "less harm" to wildlife populations. How then, can one conclusively say that this will allow previously harmed wildlife populations to recover? Is this reduced amount of "harm" bearable? Can the populations thrive in this case? By how much is the harm reduced? What is the threshold? 
Personally feel like A leaves all this unanswered.

AlexTheTrainer · Answer

The question asks for an assumption required by the argument. That is, something necessary in order for the conclusion to be true (based on the evidence/premises). The question is NOT asking for something that proves, or even strengthens, the conclusion.

A defining feature of an assumption is the negation test - negating an assumption will kill the conclusion (based on the evidence/premises). Negating (A) kills the conclusion and it thus the assumption.

Negating (A): use of crops that have been genetically engineered in place of crops that have been sprayed with insecticides will cause MORE harm to wildlife populations.

The above negation would clearly lead to a conclusion that wildlife will NOT be helped. In other words, the above negation kills the conclusion.

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Acme · Answer

Another good explanation from LSAT forum https://forum.powerscore.com/viewtopic.php?t=12155

AlexTheTrainer · Answer

A straightforward negation of C would result in “ALWAYS sprayed with insecticides”, which appears to cause a problem in the argument. However:

Always negate “some” and “sometimes” (and “many”) into “no”, “none”, etc. AND vice-versa. In the case of (C), “never” should be negated into “sometimes”.

Turning “never” into “sometimes” should seem to not affect the argument, especially since it discusses “excessive” insecticide spray. “Some” insecticide spray is just not relevant.

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nightblade354 · Answer

Farmer: Crops genetically engineered to produce toxins that enable them to resist insect pests do not need to be sprayed with insecticides. Since excessive spraying of insecticides has harmed wildlife populations near croplands, using such genetically engineered crops more widely is likely to help wildlife populations to recover.

Which of the following is an assumption the farmer's argument requires?

(C) Crops that have been genetically engineered to resist insect pests are never sprayed with insecticides that harm wildlife populations

Negation of (C): Crops that have been genetically engineered to resist insect pests are  never     sometimes   sprayed with insecticides that harm wildlife populations --  Does this statement wreck our argument that more widespread use of genetically engineered crops will benefit animals? Nope. How much spraying is required to become 'excessive' and begin hurting animals, per our argument stem? We do not know. So it is more than reasonable to say that this new amount doesn't meet our threshold. Remember, we cannot make assumptions to make our answer correct (in this case, amount required to be harmful), but we can assume information to poke holes in arguments to sink answer choices, as we just did.

Kittipop56 · Answer

Can you please explain to me why B is incorrect?  nightblade354

If I negate B, I will get

"Wildlife populations that have been harmed by the excessive spraying of insecticides on croplands  are not likely  to recover if the amount of insecticides sprayed on those croplands is reduced even slightly".

If so, the wildlife populations will not recover. As a result, the conclusion does not hold true anymore.

nightblade354 · Answer

Farmer: Crops genetically engineered to produce toxins that enable them to resist insect pests do not need to be sprayed with insecticides. Since excessive spraying of insecticides has harmed wildlife populations near croplands, using such genetically engineered crops more widely is likely to help wildlife populations to recover.

Which of the following is an assumption the farmer's argument requires?

(B) Wildlife populations that have been harmed by the excessive spraying of insecticides on croplands are likely to recover if the amount of insecticides sprayed on those croplands is reduced even slightly --  This answer choice is a tricky one. But think about what it is saying, per the negation: If we reduce slightly, we will not recover wildlife populations. OK, but what happens if we reduce more than slightly? The key here is that we are talking about, potentially, the lowest level of reduction. Similar to (C), we cannot assume what level is required to trigger a positive/negative impact.

AlexTheTrainer · Answer

Good question. This is an example of the LSAT (and more rarely the GMAT) violating grammatical rules of style.

Your correct negation of B: “Wildlife populations...are not likely to recover even if the amount of insecticides sprayed on those crop lands is reduced even SLIGHTLY”

The phrase “even slightly” seems to imply that “more than slightly”, “moderately”, “greatly”, etc. are all included in this scenario. But taken literally, as assumption questions must be, “even slightly” only means just that: slightly. Stylistically, like most answer choices, B could have been written more clearly.

Accurately paraphrasing the negation of B: “wildlife populations are not likely to recover if the amount of insecticides on those croplands is slightly reduced”

The stimulus doesn’t care about a slight reduction in insecticides.

Hope this helps.

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Rickooreo · Answer

nightblade354

Can you please tell how to eliminate option E

unraveled · Answer

Farmer: Crops genetically engineered to produce toxins that enable them to resist insect pests do not need to be sprayed with insecticides. Since excessive spraying of insecticides has harmed wildlife populations near croplands, using such genetically engineered crops more widely is likely to help wildlife populations to recover.

Which of the following is an assumption the farmer's argument requires?

(A) Use of the crops that have been genetically engineered to resist insect pests in place of crops that have been sprayed with insecticides will cause less harm to wildlife populations - CORRECT. Negation helps best.

(B) Wildlife populations that have been harmed by the excessive spraying of insecticides on croplands are likely to recover  if the amount of insecticides sprayed on those croplands is reduced even slightly  - WRONG. But the question is about how GE crops help recover. This choice doesn't imply that GE crops would help recover.

(C) Crops that have been genetically engineered to resist insect pests  are never sprayed with insecticides  that harm wildlife populations - WRONG. So what..!! Whether sprayed or not it doesn't matter. How does it helps wildlife recover is the question unanswered in this choice.

(D) Use of crops that have been genetically engineered to resist insect pests is  no more costly  to farmers than the use of insecticides on crops that are not genetically engineered - WRONG. Cost is irrelevant.

(E) If a wider use of certain crops that have been genetically engineered to resist insect pests is  likely to help at least some  wildlife populations to recover, it is likely to have that effect  only  because its use will prevent excessive and ineffective spraying of insecticides on croplands - WRONG. Out of the two aspects - toxins in GE crops and excessive and ineffective spraying of insecticides on croplands - are likely to help in their own manner. Toxins does not enter the food ecosystem of the wildlife, thus not affecting it(eventually recover) and insecticides not sprayed helps recover wildlife. All in all, this choice gives a challenge to A but being a conditional goes against it. Also the scope of wildlife is limited - a window of larger wildlife not being able to recover still persists.

Answer A.

kakarot10 · Answer

D No mention of cost in the conclusion of argument

E Argument talks about the land near forest and not cropland

C 'never sprayed' , it not the subject of discussion

Between A and B it was a struggle to choose the right answer. However , B talks about slightly reducing the spray , while the new type of genetic modified plants don't need any spray , so answer is A

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VerbalBot · Answer

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Farmer: Crops genetically engineered to produce toxins that enable

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