Keratinization is a process in which cells do all of the following EXCEPT?

Keratinization is a biological process that occurs primarily in the skin and hair, where cells progressively keratinize and undergo changes as they move from deeper layers to the skin's surface. During this process, cells dry out, change shape, and produce keratin protein, leading to the formation of tough, protective structures.

Forming the medulla, on the other hand, pertains specifically to the structure of hair. The medulla is the innermost layer of the hair shaft and is not a result of the keratinization process in epidermal cells. Instead, the medulla develops during hair growth in the hair follicle and is composed of a different type of cell arrangement and materials. Thus, creating or forming the medulla is distinct from the keratinization process, which is more concerned with the changes and lifecycle of skin or hair epidermal cells.