Immunity system  The term immunity has traditional refer to as the Resistance exhibit by the host towards injury. Causes by pathogens and their products. Immunity in fact '''freedom''' or exempt. The concept of immunity is believed to be start by "Edward Jenner" in England He develop Cowpox vaccine for the protection against small pox (virus). Immunology "The Branch of science which deals with the study of immunity system,immune response to foreign substance and their role in resistant infection bye pathogens."   Antigen "Any foreign substance invading body and capable of stimulating an immune response is called antigen."  Antibodies "The protective chemicals produced by immune cells in response to antigens are called antibodies."  Type of immunity  system (1):- Innate immunity or Inborn immunity  (2):- acquired immunity   Inborn Immunity "It is a natural defense system of the body. Ex.colastum. Acquired immunity...