Really tough CR problem..Bio-engineered Cotton..

[tusharkhatri18]

Hi,
I selected option B just because the other options were not suiting much. I applied variance test in all other options and got them incorrect. Also the option B has similar keywords as that of the premise. Please explain how option B is correct?

[HarmeetS612]

Plantings of cotton bioengineered to produce its own insecticide against bollworms, a major cause of crop failure, sustained little bollworm damage until this year. This year the plantings are being seriously damaged by bollworms. Bollworms, however, are not necessarily developing resistance to the cotton’s insecticide. Bollworms breed on corn, and last year more corn than usual was planted throughout cotton-growing regions. So it is likely that the cotton is simply being overwhelmed by corn-bred bollworms.

In evaluating the argument, which of the following would it be most useful to establish?
A. Whether corn could be bioengineered to produce the insecticide
B. Whether plantings of cotton that does not produce the insecticide are suffering unusually extensive damage from bollworms this year
C. Whether other crops that have been bioengineered to produce their own insecticide successfully resist the pests against which the insecticide was to protect them
D. Whether plantings of bioengineered cotton are frequently damaged by insect pests other than bollworms
E. Whether there are insecticides that can be used against bollworms that have developed resistance to the insecticide produced by the bioengineered cotton

The OA to this question is B.However, I am unable to get out of the following confusion:
In such question types:which of the following would it be most useful to establish?
If I am right, we look for choices that either strengthens or weakens the argument.(?)
From that point of view,B and D are both relevent.
If the Answer to D is yes, then the argument weakens.if the answer is No,the argument is strengthened.
How do you make D irrelevent ?

Thanks in Advance.

In the first sentence of the argument, the author has explicitly mentioned that the crop has been bioengineered to produce its own insecticide to work against the bollworms(specifically). So other pests do not come under the scope of this argument, hence D is irrelevant.

Correct me if I am wrong

[RonPurewal]

In the first sentence of the argument, the author has explicitly mentioned that the crop has been bioengineered to produce its own insecticide to work against the bollworms(specifically). So other pests do not come under the scope of this argument, hence D is irrelevant.

no. (d) is irrelevant, but that's not the reason why.

the reason is that we're specifically trying to explain why this year's cotton crop has been "seriously damaged by bollworms" (as per the passage). so, we know that this particular damage was not caused by any other pest.

[RonPurewal]

if you change "seriously damaged by bollworms" to just "seriously damaged" (in the passage), and change "are frequently damaged" to "can be damaged" (in choice d), then choice d would be a correct answer.

[tusharkhatri18]

Hi,
I selected option B just because the other options were not suiting much. I applied variance test in all other options and got them incorrect. Also the option B has similar keywords as that of the premise. Please explain how option B is correct?

[RonPurewal]

what is "the variance test"? that sounds like some statistical/mathematical procedure, using standard deviations and suchlike.

[tusharkhatri18]

Hi Ron,
I mean that I checked all other options except option B but got some incorrect results. I selected B only because it was looking better than rest. But still I am not convinced why option B is correct. Please explain it.

Thanks in advance.

[RonPurewal]

basically, there are two possibilities:
1/ there are way more bollworms than usual. they're just as vulnerable to the insecticide as they've always been... but there are just zillions and zillions of them now.
2/ the number of bollworms is the same as always, but the bollworms are now immune to the insecticide.

the argument thinks it's #1.

choice (b) is relevant because it will distinguish between these possibilities.
if there's more damage to the non-insecticidal plants than usual, then there must be more bollworms (possibility #1), because nothing else could explain that additional damage.
if there isn't, then there are the same number of bollworms as usual. in that case, the bollworms must be becoming more robust against the insecticide (possibility #2).