This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Antigen binding site in immunoglobulin is - 
Select and explain. 
A. Variable region, B. Hypervariable region, C. Constant region, D. Idiotype
B: Hypervariable region
Answer: B: Hypervariable region 
Explanation: The antigen combining site of the immunoglobulin molecule is at its amino terminus. - it is composed of both L and H chains. - the first 110 amino acid from the N terminal are quite variable in amino acid sequence and this region is called variable region. Reference : Anathanarayan & paniker's 9th edition, pg no: 94 <\p>