13. Why are new cells formed in an organism?

New cells are formed in an organism for several reasons:

1. Growth: As an organism grows, it needs more cells to support its larger structure. This is especially true in the early stages of life, where rapid cell division occurs to facilitate growth.

2. Repair: When an organism gets injured, new cells are needed to replace the damaged or dead cells. This is how wounds heal.

3. Replacement: Cells in our body have a certain lifespan after which they die. New cells are constantly being formed to replace these dead cells. For example, skin cells are constantly being shed and replaced.

4. Reproduction: In sexually reproducing organisms, certain cells (gametes) are produced for the purpose of reproduction. These cells are formed through a special type of cell division called meiosis.

5. Adaptation: Sometimes, new cells are formed to help the organism adapt to new environments or changes in its existing environment. For example, certain bacteria can form spores (dormant cells) when conditions are unfavorable, and these spores can germinate to form new cells when conditions improve.