What are the two main functions of mitosis?

give an example of two types of cells that never go through cell division once fully formed.

how do cell repair a cut or broken bone?

Mitosis helps in the growth by means of hyperplasia. It also helps in reproduction in single celled organisms.

Neuron and Red Blood Cells doesn't undergo cell division once formed.

Osteoblasts help in forming new bones and joining old ones after there's a fracture in bone.

Mitosis is the process by which a cell divides into two daughter cells. It helps in growth of multicellular organisms as well as reproduction in single celled organisms.

The Red blood cells are formed from the bone marrow megakaryocytes and never undergo mitosis. Same are the neurons which are formed from stem cells and never undergo cell division.

The osteoblasts come into action as the bone breaks. They diposit new calcium compounds between the broken part of bones. This leads to irregular growth of bones between them which is then remoulded and brought back to shape by osteoclasts and osteocytes.