Some reasons plant or animal cells go through mitosis include growth, tissue repair, and replacing old or sick cells.
Explanation:
When an animal or plant grows mitosis creates more cells needed to add all that new growth or mass. For tissue repair, when an animal or plant gets injured cells go through mitosis, to create more cells, to repair your injury. Finally, when cells get older or sick it is necessary to replace them with new cells so cells once again go through mitosis. Another thing mitosis does is spread chromosomes to all of its daughter cells.
