The disease caused by deficiency of vitamin D in children is: MCQ with Answer and Explanation

Explanation:
All are correct: root hairs absorb water/minerals; root cap protects meristem; elongation zone extends the root.

Explanation:
Cytokinins are plant hormones that promote cell division, delay senescence by preventing chlorophyll degradation, and stimulate nutrient mobilization. Ethylene promotes ripening and senescence, abscisic acid promotes abscission and dormancy, auxin is involved in cell elongation. Cytokinins are synthesized in roots and transported upward. They are used to prolong the shelf life of leafy vegetables.

Explanation:
Vitamin C is a cofactor for the enzyme tyrosinase, which is involved in melanin synthesis. Vitamin A is for vision, B₆ for amino acid metabolism, D for calcium.