What does the endocrine system primarily do?

The endocrine system primarily functions by secreting hormones, which are chemical messengers that travel through the bloodstream to regulate various physiological processes in the body. These hormones control important functions such as growth and development, metabolism, mood, immune responses, and reproductive processes. By releasing hormones into the bloodstream, the endocrine system helps maintain homeostasis, allowing the body to respond to changes in its internal and external environments effectively.

The other options provided relate to different systems within the body. For example, processing food for nutrient absorption is primarily the role of the digestive system. Carrying nutrients and wastes is a function of the circulatory system, which transports blood and lymph throughout the body. Encasing the body and regulating temperature involves the integumentary system, primarily the skin, which provides a barrier and helps with thermoregulation. Thus, the unique role of the endocrine system in hormone secretion distinctly identifies it from these other systems.