13. What give immunoglobulins their recognizable 'Y' or 'T' shape?
A) The disulfide bonds
B) The salt linkages
C) The arrangement of four polypeptide chains
D) The glycoproteins structure

14. What do heavy chains and light chains refer to in immunoglobulins?
A) Molecular weights of the chains
B) The number of amino acids
C) The arrangement of disulfide bonds
D) Different types of immunoglobulins

15. How many disulfide bonds hold the two heavy chains together in animmunoglobulin?
A) Six to ten
B) One to five
C) More than ten
D) None