The primary purpose of the immune system is to protect the body from infections and diseases. It functions as a complex network of cells, tissues, and organs that work together to identify and eliminate pathogens such as bacteria, viruses, parasites, and fungi. The immune system distinguishes between the body's own cells and foreign invaders, allowing it to mount an appropriate response. This system includes both innate (immediate and non-specific) and adaptive (specific and memory-based) responses. A well-functioning immune system is vital for maintaining health, preventing disease, and facilitating recovery from infections.