REM sleep makes up about ________ percent of total sleep.

Ethnic/racial bias emerges by about age 5

a. in Western cultures only. b. in Eastern cultures only. c. in every country or region where multiple racial and ethnic groups live. d. only when substantial parental bias is present.

People who have the same sexual orientations still differ in what they find enjoyable. These are

a. erotic preferences. c. sexual identity diversity. b. erotic identity. d. sexual orientation.