quiet888 wrote:
The prairie vole, a small North American grassland rodent, breeds year-round, and a group of voles living together consists primarily of an extended family, often including two or more litters. Voles commonly live in large groups from late autumn through to winter; from spring through early autumn, however, most voles live in far smaller groups. The seasonal variation in group size can probably be explained by seasonal variation in mortality among young voles.
Which of the following, if true, provides the strongest support for the explanation offered?
Correct answer will provide the reason
why young voles die more often from spring through early autumn. (This is the explanation offered.)
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A. It is in the spring and early summer that prairie vole communities generally contain the highest proportion of young voles.
Proportions within the communities of voles are irrelevant.
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B. Prairie vole populations vary dramatically in size from year to year.
Does it explain why more than usual voles die from spring through early autumn?
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C. The prairie vole subsists primarily on broad-leaved plants that are abundant only in spring.
This piece of information weakens the explanation: If there is more food to feed on, the voles should proliferate. That would result in an increased number of voles.
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D. Winters in the prairie voles' habitat are often harsh, with temperatures that drop well below freezing.
The temperatures in winter are irrelevant. Many ways to circumvent this hint.
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E. Snakes, a major predator of young prairie voles, are active only from spring through early autumn.
Does it explain why more than usual voles die from spring through early autumn?