The fact that type AB blood appears to be the result of a compromise between genes for type A and type B blood provides a good example of

Dutch infants sleep longer than American babies because:

a. they are genetically programmed to sleep longer. b. they are exposed to less sunlight than American babies. c. their parents and culture value early bedtimes and rest. d. they are cold so they stay in bed longer to conserve energy.

Adopted children

A) have trouble developing feelings of trust and love toward their adoptive parents. B) tend to have more learning and emotional difficulties than other children. C) are more like their adoptive parents than their biological parents in intelligence and personality. D) fare less well than children who return to their biological mothers.