Question ID:PT75 S3 Q25 Passage: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. Stem:The argument depends on assuming which one of the following? Correct Answer Choice:AChoice 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. Choice 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. Choice 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. Choice 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. Choice E:If industrial pollution is severe, it can create more variations in the weather than would occur naturally.