Plasma cells are activated B cells that secrete antibodies, and antibodies are manufactured by the immune system. Given these facts, the molecules secreted by activated B cells are part of the: among the following options:
- immune system
 - Organic compounds
 - Energy.
 - an organism's body
 - acetic acid
 - harmful substances
 - Chemical energy
 - Veins and arteries.


 

 immune system        