An infant responds less and less to a repeated sound, but increases its response to a slightly changed sound. What term applies to this increase of response?

Intimacy plays a more central role

a. in older friendships b. among male friends c. among female friends d. when on of the friends is depressed

In twin studies, identical twins show a higher incidence of homosexuality than do fraternal twins. What does this imply about the origins of sexual orientation?

a. Parenting practices do not seem to matter as much as genetics. b. Parenting practices seem to matter a great deal more than do genetics. c. Twins have such similar experiences that their environments must matter. d. None of the above.