Match the following:

                    Set-I                                                           Set-II

          A) Antagonists                                          i) Communicate message between two neurons and that between neurons to muscles.

          B) Agonists                                                ii) bind to receptor site and inhibit its natural functioning.

          C) Chemical messengers                    iii) Crucial to body’s communication process.

          D) Inhibitor.                                             iv) Mimic the natural messenger.

                                                                                v)  Inhibit activities of enzymes.