By what criteria is it judged that a cell is a living system?

Because the cell has all the properties of a living organism. For example, this:
reproduction.
growth.
metabolism.
irritability, etc.



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.