Organisms that cannot easily and safely remove nitrogen as ammonia convert it to a less toxic substance, such as urea, via the urea cycle, which occurs mainly in the liver. Urea produced by the liver is then released into the bloodstream, where it travels to the kidneys and is ultimately excreted in urine.
1) The antibodies destroy the antigen (pathogen) which is then swallowed and digested by macrophages. 2) White blood cells can produce antitoxins which destroy the toxins that are otherwise known as poison.
