An agonist is:

a. a substance that binds with a neurotransmitter to enhance its effects

b. a substance that blocks a hormone from applying its effect

c. a substance that activates a receptor producing the same effect as

d. a neurotransmitter a substance that prevents a receptor from receiving a hormone

Option C

Explanation:

An agonist is a chemical substance that when combined with a receptor activates it and generates the same effect as neuro-transmitter.

The receptor produces a psychological response causing an action.

Unlike antagonist which does not let the affect of the agonist to appear and inverse agonist which performs the reverse function of the agonist, an agonist causes a desired action in response to the receptor.