Ron, a toddler, takes a picture and puts it to the receiver of a phone in order to "show" it to his grandmother. This example illustrates

___________ originally evolved to regulate the motor tempo

a. Testosterone. b. Serotonin. c. Stress hormones. d. Copulins.

According to the information about social class and health in the United States,

a. social class is correlated with life expectancy, but not morbidity. b. women are less likely than men to have adequate health insurance. c. almost all of the gender differences in life expectancy can be explained by social class. d. the United States is more likely than other developed countries to emphasize disease prevention, which is especially useful for low-income people.