The various classes of immunoglobulins are differentiated on the basis of their: a)both light-chain variable segments and heavy-chain constant segments. b)heavy-chain constant segments. c)light-chain variable segments. d)asymmetry. e)antigen specificity.

Option B.

Heavy chain constant.

Explanation:

Immunoglobulin is an antibody that is produced by cell plasma and play important role in immune response of the mucus membrane. It act by recognising particular antigens like bacteria and viruses and bind to the antigens in order to cause their destruction. Immunoglobulin is classified into 5 classes base on the amount of heavy chains they contain which indicates their different level of immune response to invading antigens.

These are 1gG, 1gA, 1gM, 1gE and 1gD. Each contains different number of heavy chain constant to perform different functions of immune response at different site of location.