gwd-1-25

bloomingtrees

Q25:

The passage suggests which of the following about the accuracy of the commuter diatom’s biological clock?

1. The accuracy of the commuter diatom’s biological clock varies according to changes in the tidal cycle.
2. The unusual accuracy that characterizes the commuter diatom’s biological clock is rare among intertidal species.
3. The commuter diatom’s biological clock is likely to be more accurate than the biological clock of a species that is subject to less intense environmental pressures.
4. The commuter diatom’s biological clock tends to be more accurate than the biological clocks of most other species because of the consistency of the tidal cycle.
5. The accuracy of the commuter diatom’s biological clock tends to fluctuate when the diatom is observed under variable laboratory conditions.

A为什么不对， 根据L44-50可以看出它的生物钟是变的呀， 而且我觉得alter和vary是近义词， 难道是vary的程度太强了？

bloomingtrees

thanks !!!!!!!!!!!

shuishuiles

See the line 43, ' Biologists have concluded that even though a diatom does not realy on the environment to keep time, environmental factors can alter the period of its biological clock.' It indicates that diatom depends in the first place on its own biological clock and then depends on the external environmental factors. So Choice A is wrong, which is confirmed by  the experiment in the laboratry.