If a mutation introduces a new skin color in a lizard population, which factor might determine whether the frequency of the new allele will increase?
a)how many other alleles are present
b)whether the mutation makes some lizards more fit for their environment than other lizards
c)how many phenotypes the population has
d)whether the mutation was caused by nature or by human intervention

The answer is B) whether the mutation makes some lizards more fit for their environment than other lizards.

If a mutation introduces a new skin color in a lizard population and that mutation makes some lizards more fit for their environment than other lizards then the frequency of the new allele will increase. For example, if a mutation causes some dark skin color which can help some lizards to survive. The more lizards with dark skin color will survive, and after some time, the frequency of the new allele will increase.