If intelligence is determined primarily by heredity, which pair should show the highest correlation between IQ scores?

As children reach age 2, they

A) often use language to evaluate their own and others' actions. B) begin to engage in sociodramatic play. C) often describe themselves in terms of typical emotions. D) can correctly judge the causes of many basic emotions.

The term ______ in psychology refers to the empirical study of a topic

a. research c. experiment b. observation d. variable