Question

why is the keratinocyte no longer viable in the stratum lucidum?
a) the cell is too far to be protected by the immune system
b) the cells membrane is too thick for nutrients to pass through
c) the cell is too full of keratin to fit organelles as well
d) the cell is too far away from the source of nutrients

Explanation:

In the stratum lucidum, keratinocytes become non - viable mainly because they are far from the blood supply (source of nutrients). The deeper layers of the skin have access to nutrients from blood vessels, but as cells move up to the stratum lucidum, they are too distant. Immune protection is not the main reason for non - viability here. The membrane thickness is not the key factor, and while keratin accumulation is a feature, the lack of nutrients due to distance is the primary cause of non - viability.

Answer:

d) The cell is too far away from the source of nutrients