Approximately what percentage of our total energy output is attributable to the thermic effect of food?

a. up to 10 percent
b. up to 20 percent
c. up to 40 percent
d. up to 60 percent

Melanocytes and keratinocytes work together in protecting the skin from uv damage when keratinocytes a. provide the melanocyte with a protective shield against abrasion b. maintain the appropriate temperature so the product of the melanocyte will not denature c. maintain the appropriate ph in order for the melanocyte to synthesize melanin granules d. accumulate the melanin granules on their superficial portion, forming a uv-blocking pigment layer