What is the primary function of the immune system?

The primary function of the immune system is to defend the body against infections and diseases. This complex network of cells, tissues, and organs works together to identify and eliminate pathogens such as bacteria, viruses, fungi, and parasites. The immune system includes various components such as white blood cells, antibodies, and other proteins that recognize and respond to foreign invaders.

When the body is exposed to an infectious agent, the immune system activates to mount a response. This can involve the production of antibodies to target specific pathogens, the activation of T cells that kill infected cells, and the release of signaling molecules that help coordinate the overall immune response. The effectiveness of the immune system is crucial for maintaining health and protecting the body from a wide range of infectious diseases.

Other options focus on different bodily functions unrelated to the immune response. Regulating body temperature, producing hormones for metabolism, and assisting in nutrient absorption are important physiological functions but do not align with the primary role of the immune system in protecting the body from disease and infection.