Final answer:
Activated B cells differentiate into plasma cells, which secrete antibodies, or memory B cells, which provide rapid responses to future encounters with the same antigen.
Step-by-step explanation:
Some activated B cells are transformed into plasma cells that secrete antibodies, and others remain as memory B cells. When stimulated by antigens, B cells can differentiate into plasma cells, which are specialized for the production and secretion of antibodies, also known as immunoglobulins (Ig). These antibodies are critical for the humoral immune response, as they bind to specific antigens to help neutralize pathogens. Memory B cells, on the other hand, do not secrete antibodies immediately but persist in the body to provide a rapid response upon subsequent encounters with the same antigen.