. . . "Judy's reaction best illustrates ??? ??? ??? 24 The two-word stage of language development typically begins at the age of ________ months. ??? ??? ??? prototype We more quickly recognize that a blue jay is a bird than that a penguin is a bird because a blue jay more closely resembles our ________ of a bird. ??? ??? ??? heritability The extent to which differences in intelligence among a group of p" .