Final answer:
The stratum basale is the only epidermal cell layer that can undergo mitosis.
Step-by-step explanation:
The only epidermal cell layer that can undergo mitosis is the stratum basale. It is the innermost layer of the epidermis and contains stem cells called basal cells, which divide to form all the keratinocytes of the epidermis. This layer is responsible for the continuous renewal of the epidermis.