11. The ability of an antigen to induce an immune response does not depend on the antigen’s

A. ability to enter the thyroid
B. degree of aggregation
C. dose
D. size

12. The antibiotic penicillin is a small molecule that does not induce antibody formation. However, penicillin binds to serum proteins and forms a complex that in some people induces antibody formation resulting in an allergic reaction. Penicillin is therefore

A. an antigen
B. a hapten
C. an immunogen
D. both an antigen and a hapten