By intruding mutations, which are the ultimate source of biological diversity. I think this is it.
I think
Prometer---> Spot where transcription begins
Operator ---> On/Off switch
Terminator ---> Spot where transcription ends
Answer - D. Brain and Spinal Cord
Reasoning - With the connection between body to the peripheral nervous system and Central Nervous System or Brain and Spinal Cord it has to go through these in order to have control and complex circuit of chemical signals to be Sent/Returned.