What is the purpose of mitosis? What would happen if cells did not undergo mitosis?

Mitosis is the process of cell reproduction. A cell cannot live forever so they either divide into two new cells through mitosis or die. The main purpose of mitosis is to replicate cells. If cells would not undergo mitosis, there would be no cell divisions, and the organism could not develop or increase in size. For example, after fertilization, after a zygote is formed, it undergoes mitotic divisions and as a resulting, embryo will be developed. If there were no mitosis, the embryo would not be formed, so the organism could not be developed.