Immunity is the ability of an organism immune system to provide protection against pathogens. The immune system comprises of Innate and adaptive immune system.
The innate immune system is non-specific immune response to foreign substance and it comprises of physical barriers such as skin, chemicals and immune cells.
Adaptive immune response is specific immune response to particular antigen. It comprises mainly of T and B cells. In adaptive immune response the antibodies are produced and memory is created in exposure to specific antigen. So when next time that foreign antigen enters the body, it will produce the same specific immune response because of memory.
