How does the skin benefit a living organism A: it provides protection
B: Allows thermal energy to be passed out of the body
C: Aids in movement
D: responds to stimuli?

A. it provides protection

Explanation:

protects against invasion by more pathogenic or harmful organisms.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.