The relatively large number of new mutations that occur in the human genome in each generation is tolerable because: ______________

a. humans have excellent protein repair mechanisms.
b. compared to other organisms, changes in human proteins have relatively small effects on their cells' structures and functions.
c. humans have excellent DNA repair mechanisms.
d. most of the human genome is noncoding DNA, so few mutations affect human proteins.
e. most of the mutations occur in somatic cells, not germ cells.