You are presented with the question "The molecules secreted by activated B cells are part of the:" and the following answer choices: 
- immune system
 - Organic compounds
 - Energy.
 - an organism's body
 - acetic acid
 - harmful substances
 - Chemical energy
 - Veins and arteries.

Now knowing that plasma cells are activated B cells that secrete antibodies and antibodies are manufactured by the immune system, choose the best answer.


 

 immune system        