________ neurons carry messages to the brain

What is responsible for the circadian rhythm of wakefulness and sleepiness?

a. An area in the brain generates this rhythm b. The body responds to changes in the temperature of the environment. c. Each individual learns this rhythm by imitating others of its species. d. The body responds to the same influences that produce the tides.

The research on body weight and dieting shows that

a. about one-third of US adults can be considered overweight. b. people who are overweight and who also do not exercise are at risk for some specific health problems. c. several new diet plans are effective in producing long-term weight loss, even when people do not exercise. d. overweight people should aim to lose at least 25 pounds, or else the diet will not be effective.