___1. In order for current to flow, electrons need a good conductor to allow them to move. ___2.When a battery is connected in an circuit, electrons leave from the positive terminal of the battery, travel around the circuit, and re-enter the battery at the negative terminal ___3.A switch is used to supply the electrical energy needed for the bulb to light up. ___4.For a circuit to work, it's part must not only be complete but must be connected properly.
