文勇的新托福黄金&ccedil

Migratorydirection

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Unformatted text preview: reset an animal's circadian rhythm. Normally, internal rhythms are kept in step by regular environmental cycles. For instance, if a homing pigeon is to navigate with its Sun compass, its clock must be properly set by cues provided by the daylight/darkness cycle. 378 Mail@liuwenyong.com 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 13. Look at the four squares [ ■] that indicate where the following sentence could be added to the passage. Because the internal signals that regulate waking and going to sleep tend to align themselves with these external cues, the external clock appears to dominate the internal clock. Where would the sentence best fit? 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. The activity of animals is usually coordinated with periodically recurring events in the environment. ● ● ● Answer Choices ○Most animals survive and reproduce successfully without coordinating their activities to external environmental rhythms. ○The circadian period of an animal's internal clock is genetically determined and basically unchangeable. ○Environmental cues such as a change in temperature are enough to reset an animal's clock. ○Animals have internal clocks that influence their activities even when environmental cues are absent. ○Animals are less affected by large differences between their internal rhythms and the local solar day than are humans ○Because an animal's internal clock does not operate on a 24­hour cycle, environmental stimuli are needed to keep the biological day aligned with the solar day. 379 Mail@liuwenyong.com 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 在在在在在 1. ○1 2. ○2 3. ○4 4. ○3 5. ○2 6. ○3 7. ○1 8.○3 9. ○1 10. ○1 11. ○1 12. ○2 13. ○2 14. ○2, 4, 6 380 Mail@liuwenyong.com 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 在在在在 在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在——在在在在在在在在在在在在在...
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