Let's think step by step! The molecules secreted by activated b cells are part of the:
Options:
- (A) immune system
- (B) Organic compounds
- (C) Energy.
- (D) an organism's body
- (E) acetic acid
- (F) harmful substances
- (G) Chemical energy
- (H) Veins and arteries.
The thinking starts now:
Plasma cells are activated B cells that secrete antibodies. Antibodies are manufactured by the immune system. Plasma cells are activated B cells that secrete immune system molecules. The final answer: (A).