Final answer:
The stratum corneum is a layer of dead cells in the epidermis that helps protect the skin from microbes and dehydration, and provides mechanical protection against abrasion.
Step-by-step explanation:
The stratum corneum is the most superficial layer of the epidermis and is composed of dead cells. This layer helps prevent the penetration of microbes and dehydration of underlying tissues, and provides mechanical protection against abrasion. Cells in the stratum corneum are regularly shed and replaced by cells from the underlying layers.