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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 [#permalink]

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25 Sep 2003, 17:46
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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.
[Reveal] Spoiler: OA
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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25 Sep 2003, 22:24
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.
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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25 Sep 2003, 22:32
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 ...
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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25 Sep 2003, 22:42
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.
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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25 Sep 2003, 22:42
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.
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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25 Sep 2003, 22:46
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 ; )
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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25 Sep 2003, 22:51
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.
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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26 Sep 2003, 01:35
praetorian123 wrote:
Simple one, but got it wrong!

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?

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

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.

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

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

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

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.
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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26 Sep 2003, 09:27
My vote: C
agree with akamaibrah...
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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26 Sep 2003, 10:38
AkamaiBrah wrote:
praetorian123 wrote:
Simple one, but got it wrong!

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?

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

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.

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

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

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

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.

Thanks all for a good discussion
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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26 Sep 2003, 11:01
I have an objection, but so be it.
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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26 Sep 2003, 13:18
stolyar wrote:
I have an objection, but so be it.

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
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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29 Jun 2016, 06:42
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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30 Jun 2016, 12:08
Praetorian wrote:
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.

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.
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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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30 Jun 2016, 16:05
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.

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Re: Since 1985, pollution levels in Lake Thomas have dropped [#permalink]

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01 Jul 2016, 06:58
C

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Re: Since 1985, pollution levels in Lake Thomas have dropped   [#permalink] 01 Jul 2016, 06:58
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