AP BIOLOGY

Detailed explanation-1: -If the immune system encounters an antigen that is not found on the body’s own cells, it will launch an attack against that antigen.

Detailed explanation-2: -An antigen is a substance that triggers an immune system response, especially the production of antibodies. Antigens are present on the surface of many cells, including red blood cells.

Detailed explanation-3: -The A antigen and the B antigen are both possible blood-type-determining antigens found on red blood cells. As the names suggest, the A antigen is found in type A blood cells, and the B antigen is found in type B blood cells. Type O blood has no antigens.

Detailed explanation-4: -Your immune system reacts to foreign red blood cells when they have markers, called antigens, that are unlike the antigens on your own cells. The unfamiliar antigens trigger your immune system to make RBC antibodies to destroy the foreign red blood cells.

Detailed explanation-5: -The reaction between red cells and corresponding antibodies usually results in clumping-agglutination-of the red cells; therefore, antigens on the surfaces of these red cells are often referred to as agglutinogens.