Answer:
Role
Explanation:
Whenever any foreign particle enters the human body it's called an antigen. Because of that particle is unknown for the body. Antigen enters the body and the body's immune system activated. In white blood cells, lymphocytes are very important cells. There are two types of lymphocytes, T-lymphocytes, and B-lymphocytes. T-lymphocytes are cytotoxic cells and directly kill the antigen. While B-lymphocytes identify the antigen and produce antibodies against the antigen and then kill it.
So, antigen, antibody, and lymphocytes are very important parts of the immune system.
