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705-805 (Hard)|   Assumption|      
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The populations of certain species of amphibians have declined dramati 31 Mar 2024, 16:11
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55% (02:24) correct 45% (02:28) wrong based on 305 sessions

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The populations of certain species of amphibians have declined dramatically in recent years, an effect many scientists attribute to industrial pollution. However, most amphibian species' populations vary greatly from year to year because of natural variations in the weather. It is therefore impossible to be sure that the recent decline in those amphibian populations is due to industrial pollution.

The argument depends on assuming which one of the following?

A. The amphibian species whose population declines have been attributed by many scientists to industrial pollution are not known to be among those species whose populations do not vary greatly as a result of natural variations in the weather.
B. The variations in amphibian species' populations that result from natural variations in the weather are not always as large as the amphibian population declines that scientists have attributed to industrial pollution.
C. Either industrial pollution or natural variations in the weather, but not both, caused the amphibian population declines that scientists have attributed to industrial pollution.
D. If industrial pollution were reduced, the decline in certain amphibian populations would be reversed, and if industrial pollution increases, the decline in certain amphibian populations will be exacerbated.
E. If industrial pollution is severe, it can create more variations in the weather than would occur naturally.
 
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The populations of certain species of amphibians have declined dramati 01 Apr 2024, 02:16
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Can someone explain why and is A not C

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The populations of certain species of amphibians have declined dramati 01 Apr 2024, 13:19
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KarishmaB can you help with this one please
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The populations of certain species of amphibians have declined dramati 01 Apr 2024, 22:57
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playthegame
The populations of certain species of amphibians have declined dramatically in recent years, an effect many scientists attribute to industrial pollution. However, most amphibian species' populations vary greatly from year to year because of natural variations in the weather. It is therefore impossible to be sure that the recent decline in those amphibian populations is due to industrial pollution.

The argument depends on assuming which one of the following?

A. The amphibian species whose population declines have been attributed by many scientists to industrial pollution are not known to be among those species whose populations do not vary greatly as a result of natural variations in the weather.
B. The variations in amphibian species' populations that result from natural variations in the weather are not always as large as the amphibian population declines that scientists have attributed to industrial pollution.
C. Either industrial pollution or natural variations in the weather, but not both, caused the amphibian population declines that scientists have attributed to industrial pollution.
D. If industrial pollution were reduced, the decline in certain amphibian populations would be reversed, and if industrial pollution increases, the decline in certain amphibian populations will be exacerbated.
E. If industrial pollution is severe, it can create more variations in the weather than would occur naturally.
 
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Scientists attribute decline in populations of certain species of amphibians to industrial pollution.
Most amphibian species' populations vary greatly from year to year because of natural variations in the weather.

Conclusion: We can't say whether this decline is due to industrial pollution.

What is the assumption? That the "certain species" that scientists are talking about are a part of "most species" that the author is talking about. 
What is these certain species that have seen population decline do not get affected by weather? Then the conclusion breaks. 

A. The amphibian species whose population declines have been attributed by many scientists to industrial pollution are not known to be among those species whose populations do not vary greatly as a result of natural variations in the weather.

Exactly what we were looking for. The assumption is that these certain species that the scientists are talking about are not a part of those species that do not see variation due to weather. In simpler terms, the assumption is that these certain species that the scientists are talking about are a part of those species that do see variation due to weather.

B. The variations in amphibian species' populations that result from natural variations in the weather are not always as large as the amphibian population declines that scientists have attributed to industrial pollution.

We are assuming kind of the opposite - that the natural variations in the weather could be (or often are) as large as the amphibian population declines that scientists have attributed to industrial pollution. "not always" has a negative connotation.

C. Either industrial pollution or natural variations in the weather, but not both, caused the amphibian population declines that scientists have attributed to industrial pollution.

We are not assuming that these two are the only possible reasons or that both cannot be the reason.
In simple terms, this is what is being said:

Scientists: A is the reason for decline.
Author: B also causes such declines. So you cannot say whether A caused this decline. 

Is the author assuming that A and B are only possible causes? No. Is he assuming that both could not have resulted in the decline? No. All he is saying is that since B also cause the same effect, you cannot attribute the effect to A. He is saying that we cannot conclude what caused the decline. 

divyansh843

D. If industrial pollution were reduced, the decline in certain amphibian populations would be reversed, and if industrial pollution increases, the decline in certain amphibian populations will be exacerbated.

No assumption about what may happen in future.

E. If industrial pollution is severe, it can create more variations in the weather than would occur naturally.

"Severe industrial pollution" is out of scope of our argument. ­Our argument only talks about "industrial pollution."

Answer (A)
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The populations of certain species of amphibians have declined dramati 16 Jan 2026, 22:49
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