Since 1985, pollution levels in Lake Thomas have dropped

Question

Since 1985, pollution levels in Lake Thomas have dropped considerably, primarily because of a state program to clean the lake water by means of a water refinery. Ironically, during this same period, the once-abundant population of sunfish in the lake has dwindled.

Which of the following, if true, would best explain why the sunfish population of Lake Thomas has dwindled at the same time that the lake water has become cleaner?

A)The life spans of sunfish are not diminished by high pollution levels, but the number of offspring they create during their lifetime is diminished.

B)Several artificial chemicals are introduced into the lake as a result of the refinement process, but these chemicals are known to have a benign effect on fish.

C)The water refinement process creates an environment extremely favorable to pike, a predator fish.

D)The heaviest concentrations of sunfish population in the lake are at its northern and northeastern shores, many miles away from the water refinery.

E)Ever since 1972, a strictly enforced state regulation has prevented anglers from over-fishing Lake Thomas.

stolyar · Answer

I vote for A. The refinement has nothing to do with dwindling the sunfish population. It is previous pollutants that prevent the sunfish from breeding, and the effect of pollution simply concides with the time of refinement.

C is temptive, but we do not know for sure whether the pike preys on the sunfish. In fact, the reverse situation is possible.

ngulati · Answer

stolyar it cant be A as the population has dwindled only since the new process was put in place... so C has to be right ...

ngulati · Answer

on second thots A is right stoylar.. I reread it... as the offsprings havre reduced and the most of the fish would have died in this span. so very few remain.

stolyar · Answer

C has to be right assuming that the pike preys on the sunfish. But is this assumption valid? I think not. 

The right C should be: The water refinement process creates an environment extremely favorable to the pike, a predator fish praying on the sunfish.

As for A: the sunfish population was abundant but did not have enough offsprings. The old fish start to die; the number of the young fish is small, and even clean water cannot correct the situation.

ngulati · Answer

A small catch here mate.. what if the average fish lives for a span exceeding the period ; )then all must be alive.. so the fish dying is also an assumption ; )

stolyar · Answer

I thought about it. The CR sections requires that we take the best answer. I hope A is the best, simply the best, as Tina Turner sings. Let's wait for the official answer.

AkamaiBrah · Answer

My choice is definitely C. 

Remember, we are trying to explain the decrease in Sunfish...

(A) states that number of offspring is DIMINISHED by pollution. Hence, if we REDUCE pollution, offspring will no longer be diminished. This certainly does not explain the decrease in Sunfish -- more likely it inplies that an eventually increase will occur. 

(B) states that the chemical do not harm fish. Hence, this does not explain the decrease in Sunfish.

(C) states that a predatory fish thrives in the environment created by the refinery. Nitpicking aside, since the subject of the argument is the "sunfish", it is reasonable to assume that the term "predatory" refers to the relationship of the pike to the sunfish. This would certanly explain a decrease in sunfish and IMO is the best choice.

(D). states that the heaviest concentration of pike are far away from the refinery. While this is consistent with (C), it does not in itself explain an overall decrease in the sunfish population.

(E) does nothing to explain the decrease in Sunfish since 1985 and is irrelavent. In fact, it removes a possible explaination for the decrease.

Vicky · Answer

My vote: C 
agree with akamaibrah...

Praetorian · Answer

C is the correct answer

Thanks all for a good discussion
Praetorian

stolyar · Answer

I have an objection, but so be it.

Praetorian · Answer

Stolyar, i totally understand the objection about C.

I picked A too,but Akamai's explanation makes sense....the pollution

levels are down, so there should not be any problems with the creation of 

offspring. A doesnt help us get there...

I agree that C is way too general. but its the BEST ANSWER. 

Thanks All
Praetorian

HKD1710 · Answer

The argument makes an assumption that cleaning the lake should have given better life to sunfish. we need to find the reason for dwindling of the fish. Choice C says, hey you cleaned the lake that's fine and it should have done good to fish that's fine too but the real problem is the predator who got the better access to the fish because of clean water. This is the correct choice.

MBAPrepCoach · Answer

I would first read the question and paraphrase it as clean lake, less fish. Then I will go through each answer choice and ask, are you telling me why clean lake, less fish? C is the only answer that incorporates both of those in the answer. It talks about clean Lake, refinement, and less fish, predators. The others or less what I would call less close to home they don't use the same terminology and so it could be argued that they are out of scope, even A.

Farrell Dyan Hehn, MBA
Admissions Consultant & Verbal Tutor MBAPrepCoach.com

Farrell Dyan Hehn, MBA
Admissions Consultant & Verbal Tutor MBAPrepCoach.com

aragonn · Answer

Question Explanation:

Fact 1: Since 1985, pollution levels in Lake Thomas have dropped considerably, primarily because of a state program to clean the lake water by means of a water refinery.

Fact 2: Ironically, during this same period, the once-abundant population of sunfish in the lake has dwindled.

This is a resolve/explain question, as evidenced by the phrase which of the following…would best explain why. The fact that pollution levels in Lake Thomas have dropped considerably should help the population of the sunfish. However, during this same period, the once-abundant population of sunfish in the lake has dwindled. For an answer choice to explain this discrepancy, it must provide a reason for the dwindling population. Evaluate the answer choices, looking for one that reflects this idea.

Choice A: No. The fact that the number of offspring they create during their lifetime is diminished by high pollution levels addresses only one side of the conflict. This does not explain why the once-abundant population of sunfish in the lake has dwindled since pollution levels in Lake Thomas have dropped.

Choice B: No. The fact that these chemicals are known to have a benign effect on fish makes the conflict worse because this does not explain why the once-abundant population of sunfish in the lake has dwindled since pollution levels in Lake Thomas have dropped.

Choice C: Correct. If the water refinement process creates an environment extremely favorable to pike, a predator fish, then this would explain why the once-abundant population of sunfish in the lake has dwindled even though pollution levels in Lake Thomas have dropped.

Choice D: No. The fact that the heaviest concentrations of sunfish population in the lake are at its northern and northeastern shores is out of scope. This does not explain why the once-abundant population of sunfish in the lake has dwindled, because the passage states pollution levels in Lake Thomas have dropped, not just in portions of Lake Thomas.

Choice E: No. If anything, a strictly enforced state regulation that has prevented anglers from over-fishing Lake Thomas would make the conflict worse because this does not explain why the once-abundant population of sunfish in the lake has dwindled.

The correct answer is choice C.

VerbalBot · Answer

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Since 1985, pollution levels in Lake Thomas have dropped

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Since 1985, pollution levels in Lake Thomas have dropped

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