The correct answer is antigens and epitope.
An antigen is a substance which triggers an immune response in an organism. This can be either a foreign substance, such as a pathogen, or a specific part of the host organism (in this case this is an autoimmune response). The presence of an antigen activates a specific part of the immune system, called antibody. Each antigen has a specific antibody, which is tailored by the immune system accordingly. More specifically, the antibody has a specific structure, called paratope, which is complementary and binds like a key to a specific structure of the antigen, called epitope.
to give birth to youg one
Darwin's opinion that living forms must be descended from extinct forms was most closely related to his consideration of the fossil record.
Primary succession is a method of fertilizing soil that was barren and had never supported plant life, for example soil left over by a moved glacier of lava.
