19. What are the two types of light chains in immunoglobulins?
A) Alpha and beta
B) Kappa and lambda
C) IgG and IgM
D) Gamma and delta

20. Which type of light chain is more commonly found inimmunoglobulins?
A) Beta chain
B) Lambda chain
C) Kappa chain
D) Alpha chain

21. What kinds of immunoglobulins were first used for amino acidsequencing and crystallographic studies?
A) Macroglobulins
B) Myeloma proteins
C) Antibodies
D) Cryoglobulins