Select the mismatched pair
(a) Adrenaline: Pituitary gland
(b) Testosterone: Testes
(c) Estrogen: Ovary
(d) Thyroxin: Thyroid gland
Explanation: Adrenaline is a hormone produced by the adrenal glands and triggers the body's fight-or-flight response while the pituitary gland produces growth hormone. Testosterone is a hormone produced by the testes in males and is responsible for the development of male sexual characteristics. Estrogen is produced by ovaries in the females and is responsible for the development of female sexual characteristics. Thyroxine is produced by the thyroid gland whose function is to regulate the metabolism in the cells of the body. Hence, (a) is the correct option.