Biological Clocks Cause Organisms to Perform Daily Activities on a Regular

Multiple Choice

Biological clocks cause organisms to perform daily activities on a regular basis. Which of the following is a False statement about this kind of "circadian rhythm"?

A) It may have the same signal transduction pathway in all organisms.
B) It must be reset on a daily basis.
C) It may help to cause photoperiodic responses.
D) Once set, it is independent of external signals.
E) The exact mechanism of biological clocks remains unknown.