Psychoactive drugs affect behavior and perception through

A) the power of suggestion.
B) the placebo effect.
C) alteration of neural activity in the brain.
D) psychological,not physiological,influences.

Psychoactive drugs, by definition, alter neural activity in the brain, which in turn affects behavior and perception. While the power of suggestion or placebo effect may play a role in a person's response to psychoactive drugs, ultimately the physiological changes in the brain are what cause the changes in behavior and perception. Psychological influences may also play a role, but they are not the primary mechanism through which psychoactive drugs exert their effects.