At 6 months of age, American infants sleep about 14 hours a day, whereas infants who are the same age in Kenya sleep about 12 hours a day, and infants in the Netherlands sleep about 16 hours a day. This variation is best explained by .
a) differences in genetics.
b) cultural practices
c) innate programming.
d) random variation.

Read the following: (1) liz has become more responsive to her partner's advances since a really beautiful woman moved in next door; (2) unable to accept his desire for other young men, 15-year-old juan immerses himself into his studies; (3) shauntel tells people that her coworker mary dislikes her; though if she were honest, shauntel would realize that it is actually she who dislikes mary; (4) "ben's nasty; he's disgusting," says renee; but renee secretly finds ben attractive. describe the defense mechanism he or she is using.

What are policymakers trying to do by using the media to deliver specific messages to citizens?

To what is the growth of civilization most clearly traced