In biological terms, what is the primary function of hormones?

Hormones play a crucial role in the regulation of various bodily functions and processes. They are chemical messengers secreted by glands in the endocrine system and travel through the bloodstream to target organs or tissues, where they exert their effects. Hormones are involved in numerous physiological processes, including growth and development, metabolism, immune function, and the maintenance of homeostasis. For example, insulin regulates blood glucose levels, while thyroid hormones control metabolic rates.

The other options focus on entirely different biological functions. Structural support is more closely associated with proteins such as collagen in connective tissues. Enzymes, which catalyze biochemical reactions, are a different class of proteins that facilitate metabolic processes but do not regulate them in the way hormones do. Lastly, hemoglobin is the protein responsible for transporting oxygen in red blood cells, not hormones. Therefore, the primary function of hormones, as indicated by the correct response, is their regulatory role in various bodily processes.