<prompt> Receptor agonists possess:Affinity but no intrinsic activityIntrinsic activity but no affinityAffinity and intrinsic activity with a signAffinity and intrinsic activity with a - sign  <response>: Ans. C. Affinity and intrinsic activity with a signa. Agonist: Drug having affinity and intrinsic activity IAefficacyb. Antagonist: Drug having affinity but no intrinsic activityc. Inverse agonist: Having affinity and intrinsic activity which is opposite to that of agonist e.g. beta carbolines at BDZ receptord. Partial agonist: Drug having affinity and intrinsic activity IAefficacy less than agonist 