Final answer:
The stratum basale is the layer of the epidermis responsible for constant mitosis and giving rise to keratinocytes.
Step-by-step explanation:
The layer of the epidermis responsible for constant mitosis and giving rise to keratinocytes is the stratum basale, also known as the basal cell layer.
This layer is located at the bottom of the epidermis and consists of actively dividing cells. It is the innermost layer that comes in direct contact with the basement membrane.
As new cells are produced through mitosis in the stratum basale, they push older cells towards the surface, where they eventually become keratinized and form the outermost layer of the epidermis.
Learn more about Epidermal layers