Which hormone helps to regulate the body's metabolic rate?

• A. Aldosterone
• B. Insulin
• C. Cortisol
• D. Thyroxine (T4)

Answer: (D)

Verified step by step guidance

1. Understand the role of hormones in the body: Hormones are chemical messengers that regulate various physiological processes, including metabolism, growth, and homeostasis.
2. Identify the function of each hormone listed: Aldosterone regulates sodium and potassium balance, Insulin controls blood glucose levels, and Cortisol is involved in stress response and metabolism. Thyroxine (T4), however, is specifically responsible for regulating the body's metabolic rate.
3. Learn about Thyroxine (T4): Thyroxine is a thyroid hormone produced by the thyroid gland. It plays a critical role in controlling the rate at which the body uses energy (metabolic rate), as well as influencing growth and development.
4. Understand how Thyroxine works: Thyroxine increases the basal metabolic rate by stimulating cells to produce more energy through processes like cellular respiration. It also affects protein synthesis and the breakdown of fats and carbohydrates.
5. Conclude that Thyroxine (T4) is the correct answer: Based on its role in regulating the body's metabolic rate, Thyroxine is the hormone that directly fulfills this function.