In my own words, what is the biological clock and what is its function?

The biological clock, as its name implies, is a daily law that organisms (temporarily discussing animals and plants) should abide by. When it comes to the biological clock, we have to talk about people's daily work habits, that is, what we call 2/3 hours of labor and 1/3 hours of rest. It is better to say that the biological clock is a rule that we have to abide by, just like when you study or work every day, it is a certain time.

The biological clock varies from person to person, and there is no fixed program. The function of biological clock is like making a machine work for a while, taking a break to buffer, and then continuing to work.