Final answer:
The stratum corneum is the outermost epidermal layer made up of dead cells, providing protection and is renewed every four weeks; it does not contain melanocytes like the stratum basale.
Step-by-step explanation:
The stratum corneum is the outermost layer of the epidermis, which is composed of mostly dead cells. It acts as a barrier to protect underlying tissues from infection, dehydration, and mechanical stress. This layer is replaced every four weeks, with cells being shed periodically and replaced by new cells pushed up from the stratum granulosum. Unlike the stratum basale, which is the innermost layer of the epidermis containing melanocytes responsible for producing the skin pigment melanin, the stratum corneum does not house living cells or melanocytes. Therefore, the correct answer is: The stratum corneum is composed of mostly dead cells.