关于TPO13的一道阅读题求指点

chaserjingUID: 2858520

Biological Clocks
14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Answer Choices

1。Most animals survive and reproduce successfully without coordinating their activities to external environmental rhythms.

2。 The circadian period of an animal's internal clock is genetically determined and basically unchangeable.

3。Environmental cues such as a change in temperature are enough to reset an animal's clock.

4。Animals have internal clocks that influence their activities even when environmental cues are absent.

5。Animals are less affected by large differences between their internal rhythms and the local solar day than are humans

6。Because an animal's internal clock does not operate on a 24-hour cycle, environmental stimuli are needed to keep the biological day aligned with the solar day.
答案是1 2 6
为什么1是对的？为什么不可以选4呢？

风行拾UID: 2899495

楼主可以参考下这里的解释：

http://club.topsage.com/thread-2257706-1-1.html

evergreen7UID: 2752589

请注意第一段的这句话：
Normally, the constantly changing levels of an animal's activity—sleeping, feeding, moving, reproducing, metabolizing, and producing enzymes and hormones, for example—are well coordinated with environmental rhythms, but the key question is whether the animal's schedule is driven by external cues, such as sunrise or sunset, or is instead dependent somehow on internal timers that themselves generate the observed biological rhythms.