Question

the ______ in keratinocytes protects the epidermis and dermis from the harmful effects of sunlight.
keratin
hemoglobin
carotene
sebum
melanin

Explanation:

Melanin in keratinocytes absorbs UV - radiation, protecting the epidermis and dermis from sunlight's harmful effects. Keratin provides structural support, hemoglobin is in red - blood cells for oxygen transport, carotene is a pigment with antioxidant properties but not the main sun - protection factor here, and sebum is an oily substance for skin lubrication.

Answer:

E. melanin