12. morphine and codeine are the chief mind-affecting chemicals in the pain-relieving drug a. heroin b. opium c. methadone d. all of the above

At what age does trust usually begin to develop? a. 25 weeks b. 20 weeks c. 15 weeks d. 10 weeks

Why is a lunch consisting of pizza, fruit, and salad a better choice than a lunch with the same number of calories from pizza alone? a)both lunches provide the same amount of energy but the lunch of pizza, salad, and fruit provides more nutrients. b)both lunches provide the same amount of nutrients but the lunch of pizza, salad, and fruit provides more energy. c)both lunches are healthful but the lunch of pizza, salad, and fruit provides more energy for metabolism. d)both lunches are healthful but the lunch of pizza, salad, and fruit is likely to have a higher fat content.

Which description best defines the nervous system and its two main branches? a: the message center of the body, split into the autonomic nervous system and the somatic nervous system b: the control panel of the body, split into the central nervous system and the exterior nervous system c: the message center of the body, split into the central nervous system and the peripheral nervous system d: the control panel of the body, split into the brain and the spinal cord