Which of the following accounts for the highest morbidity and mortality rates?

Researchers have found that every addictive drug causes ______ levels in the brain to increase

a. dopamine c. norepinephrine b. serotonin d. acetylcholine

Betty's infant daughter cries often and is routinely in negative moods. She reacts to change with difficulty and slowness

According to research conducted by Thomas and Chess, this baby most likely has which of the following types of temperaments? a. anxious b. easy c. difficult d. slow-to-warm-up