You are presented with the quiz "the flow of current in what is moved up and down?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "aswitch is used to start the flow of current in an electrical circuit" and "each switch is moved up for on, and down for off".   So, what's the best answer to the question?
OPTIONS:
(A). an electrical storm.
(B). Veins and arteries..
(C). mouth of rivers.
(D). a short circuit.
(E). an electrical circuit.
(F). circulatory systems.
(G). bad wiring.
(H). a hydraulic system.
(E).