Name the plant hormones responsible for the following
(a) elongation of cells
(b) growth of stem
(c) promotion of cell division
(d) falling of senescent leaves
(a) Auxin is a plant hormone produced in the stem tip that promotes cell elongation.
(b) Gibberellin is a plant hormone that causes growth of stem.
(c) Cytokinin is a plant hormone that promotes cell division.
(d) Abscisic acid is a plant hormone that controls falling of senescent leaves.