The primary function of the immune system is to protect the body from infections and diseases by identifying and eliminating pathogens such as bacteria, viruses, parasites, and fungi. It comprises a complex network of cells, tissues, and organs, including white blood cells, lymph nodes, and the spleen. The immune system distinguishes between foreign invaders and the body's own cells through a process called immune recognition. When it detects harmful agents, it initiates an immune response that can involve producing antibodies, activating other immune cells, and forming memory cells for long-term immunity. A healthy immune system is crucial for overall well-being.