Final answer:
The keratinocytes are responsible for forming the skin's stratum corneum. They produce keratin, which gives skin its protective properties, and they replace the dead cells in the outermost layer of the epidermis.
Step-by-step explanation:
The cell type responsible for forming the skin's stratum corneum is the keratinocytes. Keratinocytes are produced from cells in the stratum basale, which go through mitosis to form new cells. As these new cells are generated, they are pushed upwards, away from the stratum basale. During this process, they produce and store keratin, a protein that provides hardness and water-resistance to the skin, hair, and nails. Eventually, these cells reach the outermost layer of the skin, known as the stratum corneum, where they are no longer living and regularly slough off, being replaced by newer cells from deeper layers. Other types of cells in the epidermis include melanocytes (which produce melanin and contribute to skin color) and Langerhans cells (which are involved in the immune response).