Final answer:
B cells are the cells responsible for humoral immunity. They produce antibodies that defend against pathogens and toxins in the extracellular environment.
Step-by-step explanation:
The cells responsible for humoral immunity are the B cells. B cells are a type of lymphocyte that mature in the bone marrow and produce antibodies, also known as immunoglobulins. These antibodies are involved in the body's defense against pathogens and toxins in the extracellular environment. The process of adaptive specific immunity that involves B cells and antibody production is referred to as humoral immunity.