As skin cells move toward the surface of the body, they produce a protein that reduces water loss. this process is called

As skin cells move toward the surface of the body, they produce a protein that reduces water loss. This process is called Keratinization.

Explanation:

Keratinization is a process which changes the stratum corneum of the skin to a hard cover which provides protection.

The process of keratinization involves polymerization of keratin polypeptides. The keratin polypeptides gets polymerized into intermediate filaments of keratin. Each of the intermediate filament of keratin constitute around 30,000 polypeptides of keratin.  

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.