单选题 3.Boreal owls range over a much larger area than do other owls of similar size. The reason for this behavior is probably that the small mammals on which owls feed are especially scarce in the forests where boreal owls live, and the relative scarcity of prey requires the owls to range more extensively to find sufficient food.
Which of the following, if true, most helps to confirm the explanation above?

A、 Some boreal owls range over an area eight times larger than the area over which any other owl of similar size ranges.
B、 Boreal owls range over larger areas in regions where food of the sort eaten by small mammals is sparse than they do in regions where such food is abundant.
C、 After their young hatch, boreal owls must hunt more often than before in order to feed both themselves and their newly hatched young.
D、 Sometimes individual boreal owls hunt near a single location for many weeks at a time and do not range farther than a few hundred yards.
E、 The boreal owl requires less food, relative to its weight, than is required by members of other owl species.

【正确答案】 B

【答案解析】Argument Evaluation
Situation The small mammals on which owls prey are relatively scarce in the forests where boreal owls live. That is why boreal owls range more extensively than do other, similarly sized owls in search of food.
Reasoning Which choice, if true, would most help confirm the proposed explanation? One way to confirm an explanation is by finding further information that one would expect to be true if the explanation is valid. If the explanation in the passage is valid, then one would expect that variations in the population density of available small-animal prey for boreal owls would be accompanied by variations in the ranges of the boreal owls. Naturally the population density of available small-animal prey is likely to be affected by how plentiful food is for those small animals.
A The comparison between different groups of boreal owls is not relevant to the comparison between boreal owls and other owls.
B Correct. This indicates that abundance of food for the boreal owls' small-animal prey in an area (and therefore abundance of small animals in that area) correlates with a smaller range for the boreal owls there. This strengthens the proposed explanation.
C This option concerns a correlation between owls' need for food and the frequency with which owls hunt, whereas the phenomenon described in the passage and the proposed explanation have to do with the range over which owls hunt.
D If one were to assume that boreal owls never hunt near a single location for weeks, that would in no way undermine the proposed explanation.
E If anything, this option tends to undermine the proposed explanation, because it suggests the possibility that boreal owls need not make up for the relative scarcity of prey in their habitats by ranging over larger areas.
The correct answer is B.