Most of the year, the hermit thrush, a North American songbird, eats a diet consisting mainly of insects, but in autumn, as the thrushes migrate to their Central and South American wintering grounds, they feed almost exclusively on wild berries. Wild berries, however, are not as rich in calories as insects, yet thrushes need to consume plenty of calories in order to complete their migration. One possible explanation is that berries contain other nutrients that thrushes need for migration and that insects lack.

Which of the following, if true, most seriously calls into question the explanation given for the thrush's diet during migration?


Hermit thrushes, if undernourished, are unable to complete their autumn migration before the onset of winter.

Insect species contain certain nutrients that are not found in wild berries.

For songbirds, catching insects requires the expenditure of significantly more calories than eating wild berries does.

Along the hermit thrushes' migration routes, insects are abundant throughout the migration season.

There are some species of wild berries that hermit thrushes generally do not eat, even though these berry species are exceptionally rich in calories.

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情景：大部分时间里，隐士画眉鸟主要吃昆虫，但是在秋天，由于它们的迁徙，它们主要的食物变成了野生浆果。但是，浆果含有的卡路里量不如昆虫，隐士画眉鸟又需要花费很多的卡路里量来完成迁徙。因此，一个解释是浆果中含有昆虫中缺乏的隐士画眉鸟在迁徙中可以用的营养物质。

推理：由于结论给出了一个对前提中现象的解释，所以本题是果因推理。
顺序的因果逻辑：因为浆果中含有昆虫中缺乏的隐士画眉鸟在迁徙中可以用的营养物质，所以隐士画眉鸟在迁徙的时候可以只吃含有的卡路里量不如昆虫的这种浆果
（果）前提：隐士画眉鸟在迁徙的时候只吃含有的卡路里量不如昆虫的这种浆果
（因）结论：浆果中含有昆虫中缺乏的隐士画眉鸟在迁徙中可以用的营养物质

选题方式：果因推理有两个评估方向，简而言之，即，要么给“隐士画眉鸟在迁徙的时候只吃含有的卡路里量不如昆虫的这种浆果”另一个原因，要么给出因果联系问题。

选项分析：

A选项：如果缺乏营养，隐士画眉鸟没有能力完成它们在秋天的迁徙。如果缺乏营养下，画眉鸟依然可以迁徙，其可以解释为什么隐士画眉鸟在迁徙的时候可以只吃含有的卡路里量不如昆虫的这种浆果，因此本选项可以加强推理文段。属于CQ1：说明结果问题。

B选项：昆虫中含有野生浆果中没有发现的营养素。本选项和推理文段的因果无关。

C选项：Correct. 对于画眉鸟来说，抓昆虫需要比吃浆果花费更多的卡路里。如果抓昆虫消耗的卡路里量比较大，那么其实吃昆虫和吃浆果对于画眉鸟来说在摄入能量总量上可能相同，其可以解释为什么隐士画眉鸟在迁徙的时候可以只吃含有的卡路里量不如昆虫的浆果。属于CQ1：说明结果问题。

D选项：在隐士画眉鸟迁徙的路途上，昆虫是足够丰富的。本选项和推理文段的因果无关。

E选项：有一些浆果是画眉鸟从来都不吃的，就算是这些浆果非常的丰富。本选项和推理文段的因果无关。

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