| Plant deficient of element zinc, shows its effects on the biosynthesis of plant growth hormone |
| a) | Ethylene | b) | Abscisic acid |
| c) | Auxin | d) | Cytokinin |
| (c)Deficiency of zinc is characterised by a reduction in intermodal growth due to which plant develops rosette habit of growth. The leaves may also be small and distorted. These results are due to loss of capacity to produce auxin (indole acetic acid) |