Final answer:
The correct answer is A) Antibody, which are molecules produced by B cells in response to foreign antigens, with a role in identifying and helping to eliminate these antigens.
Step-by-step explanation:
A substance that is produced in response to and that destroys a particular antigen is called an antibody. These molecules are crucial components of the immune system's defense mechanism against pathogens. Antibodies are produced by B cells, a type of white blood cell. When a foreign antigen enters the body, it is recognized by B cells, which then produce antibodies specifically designed to bind to and neutralize that antigen. Once bound, antibodies may directly neutralize the antigen or mark it for destruction by other immune cells.
The process through which B cells create antibodies is part of the humoral immune response. These antibodies circulate throughout the body and are on the lookout for their specific antigen. When they encounter it, they bind to it, which can either neutralize the pathogen or trigger a cascade of immune responses leading to its destruction.
Thus, the correct answer to the question is A) Antibody, as antibodies have the specific role of identifying and helping to eliminate antigens that are recognized as foreign to the body.