Farmers in Ipshaw complained that birds that typically eat insects

Question

Farmers in Ipshaw complained that birds that typically eat insects that damage crops were avoiding the town because of the scent emitted by a lemonade factory. So, the town required the factory to reduce the amount of lemony scent it emitted by 90 percent. Interestingly, the number of birds in Ipshaw has not changed significantly from what it was when the farmers brought the issue to the town’s attention.

Which if the following, if true, best explains the outcome?

(A) While the factory was in the process of reducing the amount of lemony scent it emitted, farmers in Ipshaw allowed habitats that attract birds to develop around their fields.

(B) It took the factory almost a year to sufficiently reduce the amount of lemony scent it emitted to satisfy the town’s requirement.

(C) Before the town required the factory to reduce the amount of lemony scent it emitted, the scent was so strong that it caused some types of insects to avoid Ipshaw.

(D) In the region in which Ipshaw is located, the number of types of birds that are repelled by a lemony scent is similar to the number of types attracted by it.

(E) Not only birds that are beneficial to farms but also some types of birds that damage crops are repelled by a strong lemony scent.

Source:  Marty Murray Coaching

VivekSri · Answer

It was a very good question  MartyMurray . Thanks for this.

OA is D.

Farmer is saying that birds that typically eat insects that damage crops were avoiding the town because of the scent emitted by a lemonade factory.

Let us take an example, previously birds that typically eat insects were 1000 and now they are only 200, so they are 800 birds were not coming.

But the number of birds(Keep in mind in this whole birds are there including those which don't eat insects) is still the same.

So let us take an example, Previously 5000 birds were seen and now also 5000 birds are there after farmer highlighted this.

So how come this is possible? It should 4200 as 800 insects eating birds were not there? This means that there are some others birds are coming which is compensating this. Clearly written in D.

Let us start option Elimination:

Which if the following, if true, best explains the outcome?

(A) While the factory was in the process of reducing the amount of lemony scent it emitted, farmers in Ipshawaw allowed habitats that attract birds to develop around their fields. ->  how the birds are same, no where it is written. wrong

(B) It took the factory almost a year to sufficiently reduce the amount of lemony scent it emitted to satisfy the town’s requirement. ->  But how the birds are same before and after, no where written. Wrong.

(C) Before the town required the factory to reduce the amount of lemony scent it emitted, the scent was so strong that it repelled some types of insects from Ipshawaw. -> S o it is further stating that inseacts are now less, resulting in more lesser insect eating birds, again lesser number of birds. But how the birds are same before and after, no where written. Wrong.

(D) In the region in which Ipshawaw is located, the number of types of birds that are repelled by a lemony scent is similar to the number of types attracted by it. ->   This is actual answer. So it means 800 birds that were out were compensated by new type of birds.
  
(E) Not only birds that are beneficial to farms but also some types of birds that damage crops are repelled by a strong lemony scent.  ->  Out of scope.

Aabiyeh · Answer

For this question, the ans suggested is D.
But I do not understand how?
I did C, and my reasoning was that since the lemony scents repelled few insects as well, thus there was not enough feed for the birds and they did not come back and despite the fact that the insects were reduced, villagers still wanted the birds to come back is because of the remaining insects.

But the solution says D. How does influx of other birds will effect the population of earlier bird, and if the 2nd kind of bird is similar to the first kind of bird won't they be eating the insects, so why will the villagers would want the old birds back?

VivekSri · Answer

Hi  Aabiyeh , I think you missed the last part that insects is same before and after villager pointed out that.

So previously if 5000 birds are there, still insects eating birds are lesser still 5000 birds are there.

What villager wanted is not the answer. Answer should cover that how birds are same.

Aabiyeh · Answer

Thank You so much, It was very helpful.

snoopypop · Answer

I rejected D because of the units: The number of types of birds =/= the total number of birds. It’s possible that Ipshaw has 5 types of pro-lemon birds and 5 types of anti-lemon birds, but the rarity of the types differs (e.g., each pro-lemon type has 2 birds and each anti-lemon type has 200).

I wasn’t a huge fan of B (there’s obviously no evidence that the observation in the final sentence occurred before one year elapsed), but D felt like too big of a stretch, and the other answers were too ambiguous and/or weakened the claim. As such, B seems more correct.

Posted from my mobile device

DmitryFarberMPrep · Answer

It's important to keep in mind that we're not trying to prove anything here; we're just trying to explain the discrepancy we've read about. So for D, we already KNOW the number of birds has stayed the same. We just want to know why. So if a reasonable number of bird species are drawn TOWARD the scent, that could explain the similar overall numbers. It doesn't tell us why the numbers are about the same, but it doesn't have to. We now know that the missing birds were replaced with others, and the data tells us that the actual numbers of birds did indeed balance out.

We don't care about B because however long it took, the requirement has now been met, and the argument tells us that the number of birds NOW is the same as before. So we're still left wondering why the number hasn't changed. We might be interested to know how long it's been SINCE the change was completed (maybe the birds haven't had time to come back), but B doesn't say anything about that. Whether the change took a day, a year, or a century to make doesn't tell us anything concrete about why the birds aren't back yet.

gmatophobia · Answer

Paradox: The bird population did not change   significantly   even after the amount of lemony scent emitted by the factory was reduced by 90 percent.

Hence, the correct answer should logically explain why the bird population didn't change significantly despite the reduced lemony scent.

Answer choice elimination

(A) While the factory was in the process of reducing the amount of lemony scent it emitted, farmers in Ipshaw allowed habitats that attract birds to develop around their fields.

While creating bird-friendly habitats could attract more birds, the option doesn't explain why did the town not see an increase in bird population despite the reduction in the lemony scent. We can eliminate Option A.

(B) It took the factory almost a year to sufficiently reduce the amount of lemony scent it emitted to satisfy the town’s requirement.

This option is out of scope. The timeline doesn't necessarily matter and is not what we are trying to resolve. Hence, we can eliminate this option.

(C) Before the town required the factory to reduce the amount of lemony scent it emitted, the scent was so strong that it repelled some types of insects from Ipshaw.

This option provides information about the effect the lemony scent had on insects before the factory was required to reduce the amount of lemony scent it emitted but doesn't directly address why the bird population did not significantly increase after the reduction in scent. Therefore, it does help resolve the paradox. Eliminate C.

(D) In the region in which Ipshaw is located, the number of types of birds that are repelled by a lemony scent is similar to the number of types attracted by it.

A good one to consider. This option directly addresses the impact of the scent on the  total  bird population. If the number of birds repelled and attracted is roughly equal, the overall bird population wouldn't change significantly, explaining the observed outcome. Hence, we can keep this option.

(E) Not only birds that are beneficial to farms but also some types of birds that damage crops are repelled by a strong lemony scent.

Option E doesn't help us address the paradox. While some harmful birds might be gone, the option doesn't help address why the overall population level remained unchanged. Hence, we can eliminate E.

Option D

KushagraKirtiman · Answer

Wrong, The passage says in the first line that number of birds were avoiding the town which means the number of birds reduced . Moreover in the third sentence, it says that even when the factory reduced its emissions still the population of the birds in the town did not increase. So this means that the population of the birds is fewer compared to before.( Interestingly, the number of birds in Ipshaw has not changed significantly from what it was when the farmers brought the issue to the town’s attention = So when farmers bought this issue, population of birds was less than before)

SO D is wrong because it says that the population of the birds were same. Also, it does not explain why birds that are attracted by the scent stayed after the scent was removed, they could have migrated somewhere else and birds that were repeled by the scent would have come back. So D is very weak. C much better explains why the birds in question didnt come back. I think this question is just a desperate attempt to transform a simple CR question to 800 level question.

MartyMurray · Answer

Take another look. "Has not changed significantly" does not mean "decreased."
 
(C) is about insects, which presumably would have come back in that case once the scent was eliminated. So, it does not explain why birds would not have come back. After all, (C) is about the conditions that existed before the scent was eliminated.

You can learn a lot from this question by going back and seeking to better understand the timing and directions of the causes and effects in the scenario.

KushagraKirtiman · Answer

Hi Marty, 
Thanks for the explanation, but I still dont get why Birds who were attracted by the scent stayed there when the scent was substantially reduced. My line of logic is when factory stopped emitting the scent, the birds that were attracted by it should have gone somewhere else because the main reason why the new set of birds were there was because of the scent. The final line of the question says that the number of birds did not change which means the birds that came stayed there even though 90% of the scent was removed. The passage doesn't give any hint or a reason to believe that the birds once migrated to an area cannot go somewhere else.

What Option D does, it explains the reasons that some new species of birds, who presumably do not eat the insects in question came to the place, and because of it the number of birds did not change but my counterargument is that when the scent was removed by 90% there should have some birds that would migrated back or went to some other place because whole reason the birds came was the scent. So if we go by D it would be safe to assume that yes some birds stayed even though the scent was reduced but at the same time some birds would have migrated because the scent was substantially reduced which would leave no incentive for the all the Birds that came to stay there. Saying that the number of birds did not change means none of the birds who came for the scent did not migrate even though the scent was substantially reduced. I think that this inference too big of a stretch and has a lot of ifs and buts.

On the contrary, C seems to be much better, as it does explain why the number of birds did not change after the scent was removed. It gives a reason that since the insects went to some other place the birds also followed them. I do agree with your counter argument but the same argument can be applied to the birds that came because of the scent. Like you said insects would have come back after the scent was removed similarly the birds that migrated because of the scent would have gone to some other place when the scent was removed. I prefer C here because maybe the scent of the factory was poisonous for the insects and therefore the insects would not come back because 10% of the scent was still there. The passage does not say anywhere that the scent was totally removed, it explicitly mentions that 90% of it was removed so maybe 10% of the scent was enough to lower the number of insects in the place and because of it the number of birds dependent on it also reduced.

As I believe both the options are weak as there are a lot of ifs and buts. Can you give your thoughts about this ?

MartyMurray · Answer

Hi Kushagra.

They didn't stay there. They left.
 
The presumed course of events is the following:

First, the scent was strong. So, birds that eat insects were not there and birds that are attracted to the scent were there in larger than normal numbers.

Then, the scent was almost entirely eliminated. So, birds that eat insects came back, and many birds that are attracted to the scent left.

So, we see that the total number of birds remained about the same from the time the scent was there to the time it was gone because some birds came back and others left.
 
Your reasoning is correct, except in that it misses that the point is not that the birds stayed. The point is that some left and some came, with the end result that the total number remained about the same.
 
(C) doesn't tell us much about the birds. All it really implies is that the number of insects probably increased after the scent was reduced, but there were insects there anyway, as we know from the fact that farmers were complaining. So, regardless of whether there would have been more insects, there were still insects there to attract birds.

VerbalBot · Answer

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Farmers in Ipshaw complained that birds that typically eat insects

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