Final answer:
The primary purpose of mitosis in complex multicellular organisms, such as humans, is to maintain tissue growth and repair. It allows for the production of identical cells, which are needed to replace damaged or dead cells in the body.
Step-by-step explanation:
The primary purpose of mitosis in complex multicellular organisms, such as humans, is to maintain tissue growth and repair. Mitosis allows for the production of identical cells, which are needed to replace damaged or dead cells in the body. This process ensures the continuous growth and maintenance of tissues throughout an organism's life. It is not primarily responsible for generating genetic diversity or producing gametes (sex cells).