[___A___] аre prоteins prоduced by B cells. [___B___] аre prоduced when the immune system detects [___C___]. [___D___] might be molecules on the surfаce of invading pathogens that stimulate an immune response. [___E___] might also be molecules on the surface of toxins or pollens. [___F___] are foreign to the body, whereas [___G___] are produced by the body.