Zinc is essential for

A. Biosynthesis of IAA

B. Oxidation of carbohydrates

C. Stomatal closing

D. Stomatal opening

Answer: Option A

Solution(By Examveda Team)

Zinc is essential for the Biosynthesis of IAA.
Zinc activates tryptophan synthetase, which regulates the synthesis of tryptophan, involved in the biosynthesis of indoleacetic acid (IAA), hence, its main effect is on the meristematic areas involved in the foliar expansion and shoot growth.