During the elementary school years, children develop a sense of

What percentage of zygotes have an abnormal number of chromosomes?

< 1 percent 20 percent–25 percent 5 percent–10 percent > 50 percent

One of the most important discoveries that emerged from Masters and Johnson's research on sexual responding was that

a. erotic stimuli are entirely psychological. b. problems in sexual responding are almost always physiological in nature. c. psychological processes play a role in both sexual arousal and sexual satisfaction. d. therapy is likely to be ineffective in correcting problems in sexual responding.