Orphan families are families of genes that: A: Lack homologs in other species. B: Have no known function. C: Have no phenotypic change after gene inactivation. D: Have not yet been studied.

A selective sweep refers to what? A: The replacement of pre-existing genetic variation by the variation surrounding a selected allele B: Natural selection that targets a particular--"selected"--allele C: An advanced cognitive capability observed in expanded human social networks D: Patterns of phenotypic variation associated with assortive mating