IMMUNOLOGY

Detailed explanation-1: -That is, the immune system must be able to distinguish what is nonself (foreign) from what is self. The immune system can make this distinction because all cells have identification molecules (antigens) on their surface. Microorganisms are recognized because the identification molecules on their surface are foreign.

Detailed explanation-2: -Autoimmunity is caused by the breakdown in self and nonself discrimination. Autoimmunity is not caused by the lost of discrimination of self by innate immunity since non-vertebrates do not develop autoimmune disease, as evolution has only selected germ-line system of discrimination of nonself pathogens.