What process controls number of cells in various tissue?

Answer 1

Your question is a little vague to have a specific answer but there are a few processes that are used throughout the body. One of the most common is something we call density inhibition. This is where cells communicate where they are to each other so that the cells know how many of themselves make up a certain tissue. If the communication indicates that the tissue has too many cells, they will stop diving and some could even activate pathways that will destroy themselves.