Both auxins and cytokinins are growth promoting hormones in plant metabolism. They are synergistic for a physiological process ‘A’ and antagonistic for a process ‘B’. A and B are respectively

 Auxins and cytokinins are synergistic for a physiological process cell division and antagonistic for a process apical dominance  ( auxins promotes apical dominance and cytokinins prevents apical dominance by inducing growth of lateral branches)