<prompt> Which of the following is true for receptor action of the drugAn antagonist has both an intrinsic activity and affinity for receptorAn antagonist has the affinity but no intrinsic activity for the receptorA paial antagonist has no affinity or intrinsic activity for the receptorIntrinsic action and affinity are not impotant for drug action  <response>: Ref-KDT 6e p41 Intrinsic activity is a measure of the ability of a drug that is bound to the receptor to generate an activating stimulus and produce a change in cellular activity. Both agonists and antagonists can bind to a receptor. 