Immune system
The immune system is a system of biological processes and structures in the body that protects against disease. To function properly, an immune system has to detect a wide variety of agents, known as pathogens - like viruses and parasitic worms, and distinguish them from the body's own healthy tissue. Weak immune system can lead to getting sick easier, slower and harder curing. Disorders of the immune system may result in autoimmune diseases, inflammatory diseases or even cancer.