IMMUNOLOGY

Detailed explanation-1: -Each B cell clone makes antibody molecules with a unique antigen-binding site. Initially, during B cell development in the bone marrow, the antibody molecules are inserted into the plasma membrane, where they serve as receptors for antigen.

Detailed explanation-2: -B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors.

Detailed explanation-3: -They are produced in response to environmental stimulants, such as bacteria. These antibodies are produced after birth, reaching a peak at 5–10 years of age, and declining with increasing age.