Mitosis takes place in the basal layer, also known as the stratum basale, which is the deepest layer of the epidermis.

Here's why:

* Cell division: The stratum basale is the only layer of the epidermis where cells actively divide by mitosis.

* Renewal: This constant division and upward migration of cells is what replaces older, dead cells that are shed from the surface.

* Keratinocytes: The majority of cells in the stratum basale are keratinocytes, which are responsible for producing keratin, the protein that makes up skin.

While mitosis occurs in the stratum basale, the process of cell differentiation and keratinization continues as the cells move upwards through the other layers of the epidermis.