Why does cell division remain important to an adult organism even after it is fully developed?

A/new cell are needed to help the adult grow larger

B/ new cell are needed to replace worn out or damaged cells

i'd say that the moon rock is about 2.2 billion years old.

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.