This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anitibody, Subject name: Microbiology
IgM is: 
Select and explain. 
A. Monomer, B. Dimer, C. Pentamer, D. Tetramer
C: Pentamer
Answer: C: Pentamer 
Explanation: Ans. (c) PentamerRef: Anatnayayan 9/ e page 98AntibodyEffective valency* IgM5* IgG2* IgD2* IgE2* IgA2,4Also Know* Ig having maximum molecular weight: IgM* First antibody produced by newborn: IgM* All immuniglobulin are heat stable EXCEPT: IgE* Ig present in breast milk: IgA* Ig with maximum half life: IgG* Ig with minimum half life: IgE* Ig having maxilum serum concentration: IgG * Ig having least serum concentration: IgE