You are presented with the question "What is used to start the flow of current in an electrical circuit?" and the following answer choices: 
- energy
 - a doorbell
 - heat energy
 - kinetic energy
 - simple
 - Firecrackers
 - cycles
 - deltas

Now knowing that aswitch is used to start the flow of current in an electrical circuit and some systems have an additional connection for a second doorbell switch, choose the best answer.


 

  a doorbell       