Which of the following are plant hormones?
A. Insulin
B. Auxin
C. Thyroxin
D. Cytokinin
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B and D only
Plant hormones (phytohormones) are chemicals made in small amounts inside plants that control growth and development. The main groups are auxins, gibberellins, cytokinins, abscisic acid and ethylene.
A. Insulin Incorrect. Insulin is an animal hormone, made by the beta cells of the islets of Langerhans in the pancreas; it lowers the sugar level of the blood.
B. Auxin Correct. Auxin is made at the shoot tip and makes cells grow longer; it helps the shoot bend towards light.
C. Thyroxin Incorrect. Thyroxin is an animal hormone made by the thyroid gland from iodine; it controls the rate of metabolism.
D. Cytokinin Correct. Cytokinins promote cell division and delay the ageing of leaves; they are plentiful in growing regions such as fruits and seeds, and in coconut milk.