Hormones

Hormones are chemical messengers that regulate physiological processes, and glucose homeostasis depends on a pair acting in opposition. Insulin, a polypeptide hormone, is released when blood glucose is high; it promotes the uptake of glucose by cells and its storage as glycogen, thereby lowering the blood glucose level. Glucagon, also secreted by the pancreas, acts antagonistically: when blood glucose falls, it stimulates the breakdown of stored glycogen into glucose, raising the blood glucose level. Hence insulin lowers and glucagon raises blood glucose, giving the first option. The choice claiming both raise glucose ignores their antagonistic relationship and would make regulation impossible. Reversing the two roles contradicts their well-established physiology, since a deficiency of insulin, not glucagon, causes the elevated blood sugar of diabetes mellitus. The claim that they act only on protein metabolism misstates their primary function in carbohydrate regulation. This is consistent with the NCERT discussion of hormones as messengers maintaining balance. As a plausibility check, the opposing actions form a feedback loop that keeps blood glucose within a narrow range, which is exactly what a stable regulatory system requires.