Although an insecticide may initially prove effective in reducing mala

Can u mention excerpts from the argument that says that Lifecycle shoul continue.

If u are cosidering the highlighted part mentioned below than its wrong.
Because the presence of older mosquitoes—those ten or more days old—is essential to maintaining the life cycle of the malaria parasite,
The argument is concerned with killing the older mosquitoes especially the ones which are more than 10 weeks old because they help in thriving the life cycle.
I request gmatbull to post the OE

Responding to a pm:

Definitely a tough one.

The problem is that you need to read the stimulus at least twice just to understand it. The scene is something like this:

Say there are lots of mosquitoes and you spray insecticide to control malaria. Now what happens when quite a few mosquitoes die? The leftover ones are immune to insecticide and have little competition so they breed uncontrollably. Next time when you spray, the mosquito population doesn't get affected since they are mostly immune.
The solution proposed is this: Older mosquitoes are essential to maintaining the life cycle of the malaria parasite. Target only them instead of the entire mosquito population. There is still competition but an essential part of maintaining the life cycle of malaria parasites is missing.

(B) strengthens the 'there is still competition' part of the argument. If older mosquitoes have already bred, this will ensure a thriving mosquito population which means enough competition so that the insecticide immune mosquitoes do not take over.

Fame,
I would say you are confused because this is a poorly written question. In a good GMAT CR question, it may be confusing when thinking it through, but when the OA & OE are revealed, everyone has an "aha!" and feels that it makes sense.

I tend to agree with VeritasPrepKarishma's excellent analysis above. In her view, the scientists want to kill mosquitoes but leave the inter-mosquito competition intact. If they kill the older mosquitoes, this will have the advantage of killing mosquitoes that are "essential to maintaining the life cycle of the malaria parasite" without reducing genetic competition in the mosquito population. Among other things, the question expect the non-scientist reader to know that, by the "malaria parasite", they mean the protist that cause malaria, i.e. that malaria is carried by a parasite that lives in the mosquito. I think the question demands a bit too much outside knowledge of science --- I don't think the GMAT would automatically expect the reader to know the details of how genetic competition plays out or the details of how malaria is carried or transmitted. I think it's very very easy to write a hard CR question if it involves specialized knowledge of some scientific field, knowledge that maybe folks learned at one time in high school but is not uppermost in their minds. I think it's much harder to write a CR question that treats everyday topics that are well-known to everyone, that is puzzling to many readers on first reading, but that makes complete sense to everyone once the OE is given. The GMAT does this consistently with its CR question. This particular question falls well short of that standard.

That's my 2¢

Mike
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Although I picked 'E', I am not fully convinced with any of the answer options. Can an expert please explain ?

This an old thread, but I want to add something on this question. I was confused between options B & E, and ended up picking option E.
Surprise! OA is B (as is always the case with me when I am confused between two options).

After some analysis, I realized that when I was actually solving the question, it did not occur to me that the scientists wanted to target the older mosquitoes using pesticides only! I thought scientists may target the older ones thru some other means, a crucial misunderstanding that actually makes option E seem better than B.

Imo in order to accept B as the answer, the focus should be on the sentence ‘ researchers have proposed addressing the problem of pesticide resistance by searching for a means of targeting only older mosquitoes for elimination. ‘

We are looking to address the pesticide resistance issue not getting rid of malaria nor all mosquitos, thus if we choose B. The older mosquitoes have completed their breeding activity. , we solve the pesticide resistance issue by eliminating only the older mosquitos.

Let me know whats up.
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shouldnt it be E? I dont even understand hw B affects the case.

First we must make sure we understand the author's reasoning: insecticide kills some mosquitos, but those that survive pass on their resistance to their offspring, making mosquitos harder to kill with insecticide.

Now, since Malaria needs 'older' mosquitos, some people say, "well, find a way to kill those things, to help avoid this 'resistance problem.'

But... What if those older mosquitos still produce offspring? Whatever method we use to eliminate them, insecticide or otherwise, if some survive and then have offspring, and pass on that resistance to their offspring... we have the same problem. Mosquitos who are resistant to our means of killing them. Malaria can run wild.

But if the older mosquitos haven't had offspring, then who cares if some survive our new tactics of targeting older mosquitos. They won't pass that resistance onto any offspring, so this plan will better solve our problem.

E doesn't strengthen the argument. E is a wrong answer choice I think of as 'raising the stakes,' but not strengthening the argument. If older mosquitos are more resistant to insecticide than younger mosquitos... How does that strengthen the idea that we should use the researchers proposal that we *should target older mosquitos?* How does the fact that the older mosquitos are harder to kill mean we should target them?

But here's the temptation: "Malaria shows up in older mosquitos" (oh dang, well those are the ones we need to target!) "And they're harder to kill with insecticide than younger mosquitos!" (OH NO! Well then we REALLY better kill'em!)

The second doesn't *really* strengthen the first though. It just makes the first seem like a 'bigger deal.'
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