Answer:
option D, smaller; fewer cells dividing
Explanation:
With aging a cell's performance slows down and after a certain period of time it dies. In this way several cell die in an aging person , thereby making an organ less functional.
The number of living and functional cells in testes, ovaries, liver, and kidneys decreases markedly with aging.
As a cell dies, it shrinks and reduces in size thereby expelling liquid out of it.
Also the rate of formation of new cells reduces with progressing age.
Therefore, as a person becomes old the cell reduces their size and hence die. Also the cell division process becomes slow
Option D is correct