The switch of one B cell from producing one class of antibody to another class of antibody that is responsive to the same antigen is due to the rearrangement of immunoglobulin heavy-chains region DNA
Types of Immunoglobulin
Immunoglobulins were discovered in 1890 by two immunologists, Emil von Behring and Kitasato Shibasaburo, and were first referred to as neutralizing substances.
Immunoglobulins are Y-shaped globular proteins with a molecular weight of 150kDa and a size of roughly 10nm.
This Y-shaped structure is split into two parts:
The bottom section is referred to as a constant zone & top, the two-arm portion is referred to as a variable region.
Hence, the correct answer is option D
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