Answer: Option 4: replaced.
Explanation: Mitosis helps in the replacement and regeneration of new cells. When an organism is injured, mitosis occurs to replace the damaged cells, especially in skin and blood vessels. Mitosis also helps replace blood lost through a wound. In certain organisms, like lizards, mitosis can replace entire lost limbs such as tails or legs. Mitosis helps in the production of identical copies of cells and thus helps in repairing the damaged tissue or replacing the worn-out cells.