Which of the following describes a primary function of the endocrine system?

The primary function of the endocrine system is to regulate metabolism through hormones. Hormones are chemical messengers produced by various glands in the endocrine system, such as the thyroid, pancreas, and adrenal glands. They are released into the bloodstream and travel to target organs or tissues, where they invoke specific physiological responses.

Metabolism encompasses a range of biochemical processes—including catabolism (breaking down molecules for energy) and anabolism (synthesizing necessary compounds)—that are essential for maintaining homeostasis and providing the energy required for bodily functions. For example, insulin produced by the pancreas plays a crucial role in regulating blood glucose levels, thus influencing energy metabolism.

The other options provided refer to functions mainly associated with different systems in the body. Muscle contractions are primarily regulated by the nervous system and the muscular system. Blood cell production occurs in the bone marrow, which is part of the hematologic system. The storage of vitamins and minerals is a function typically attributed to organs such as the liver or bones, but not a direct function of the endocrine system.