What phenomena, repeating in nature, could be chosen as a standard of time?

Falling water droplets from a certain height.
The duration of the earth’s day.
Observing the movement of stars, the sun, the moon, or anything else.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.