Answer:
An antibody is a protein that is produced by the immune system. Their main job is to protect the body from invaders like bacteria, viruses, and parasites, which are collectively called, antigens. Chemical substances are also considered an antigen. These antigens trigger the production of antibodies as an immune response and seek and destroy them. An antigen like a virus encounters a B-lymphocyte (B-cell) first, which will produce antibodies that matches it. These antibodies will stick to the virus, marking them for the t-lymphocytes to recognize and attack.
