The primary antibody of exocrine secretions is ____________
(a) IgA
(b) IgE
(c) IgG
(d) IgM
This question was posed to me in an international level competition.
I want to ask this question from Complementary Interactions Between Proteins and Ligands: The Immune System and Immunoglobulins in chapter Three Dimensional Structure Of Proteins and Protein Function of Biochemistry