8. Excessive amounts of the neurotransmitter ______ may increase a person’s predisposition to schizophrenia. (A)serotonin (B) acetylcholine (C) dopamine (D)norepinephrine

14. By pairing the ringing of the bell with the presentation of meat, Pavlov trained dogs to salivate to the sound of a bell even when no meat was presented.In this experiment, the presentation of the meat was the _______. (A)unconditioned response (B) conditioned response (C) unconditioned stimulus (D)conditioned stimulus