What is the result of an increase in metabolic rate stimulated by thyroxine?

An increase in metabolic rate stimulated by thyroxine leads to increased energy expenditure. Thyroxine, a hormone produced by the thyroid gland, plays a crucial role in regulating metabolism, which is the process by which the body converts food into energy. When the metabolic rate rises, the body's energy demands increase, resulting in higher energy expenditure.

Higher metabolic rates facilitate various physiological processes, including the breakdown of carbohydrates, fats, and proteins, enhancing the body's ability to use these nutrients for energy. This is particularly important for maintaining vital functions, growth, and responsiveness to stimuli.

The other options do not accurately describe the effects of increased metabolic rate due to thyroxine. For instance, decreased energy consumption would contradict the concept of increased metabolic activity, while enhanced protein synthesis generally occurs under specific conditions rather than as a direct outcome of elevated metabolic rate alone. Similarly, reduced blood flow is not a consequence of increased metabolism; during heightened metabolic activity, blood flow often increases to supply necessary oxygen and nutrients to tissues.