Thyroxine is primarily associated with which physiological processes?

• A. Cortisol
• B. Insulin
• C. Thyroxine
• D. Growth hormone

Answer: (C)

Thyroxine sets the body's metabolic pace. This thyroid hormone increases the basal metabolic rate, pushing cells to use more energy, produce more heat, and run more oxidative processes. It also supports growth and development, especially of the nervous system in early life, and it helps tune cardiovascular responsiveness. So when a question asks which processes are associated with thyroxine, the best match is the hormone itself, since its main roles are regulating metabolism and development. The other hormones listed govern different functions—cortisol with stress responses and glucose production, insulin with blood glucose control, and growth hormone with growth and tissue synthesis—rather than the broad metabolic regulation that thyroxine provides.