An estimate of the variance within a population that is due to heredity is known as

A) fraternal transfer.
B) identical transfer.
C) heritability.
D) sex-linked variability.

Heritability refers to the degree to which genetics contribute to variation within a population. It is an estimate of the proportion of total variation in a trait that is due to genetics. It does not refer specifically to fraternal or identical twins (choices A and B) or to sex-linked genes (choice D).