What is a primary function of the immune system?

The primary function of the immune system is to protect the body from infections. This system comprises a network of cells, tissues, and organs that work together to defend against pathogens such as bacteria, viruses, fungi, and parasites. When these harmful invaders are detected, the immune system responds by activating various immune cells that target and neutralize the threats. This includes the production of antibodies, the activation of white blood cells, and the mobilization of other components to eliminate the pathogens, thereby maintaining the body’s health and ensuring survival.

In contrast, regulating hormone levels, facilitating digestion, and assisting in physical movement pertain to other physiological systems. Hormones are primarily regulated by the endocrine system, digestion is managed by the digestive system, and physical movement is primarily governed by the muscular and skeletal systems. Each of these systems has its dedicated roles, distinctly separate from the immune system's primary function of defense against disease.