Opiates Have a Molecular Structure That Is Similar to Endorphins,our

Multiple Choice

Opiates have a molecular structure that is similar to endorphins,our body's natural pain relievers.When Ahmed takes cold medicine with codeine in hopes of relieving a headache,the codeine stimulates the receptor sites that receive endorphins.Codeine is therefore a/an

A) agonist.
B) antagonist.
C) antipsychotic.
D) amphetamine.