Fact 1: Powering an electrical device with a battery requires a path for electricity to flow through a closed circuit.

Fact 2: Electric cars have big batteries instead of engines.

Given the two facts above, answer the question "An electric car requires what to operate?" with the following options: 
- radiation shielding
 - hydrogen and oxygen
 - electromagnetic energy
 - gasoline
 - direct energy
 - heat energy
 - a closed circuit
 - oxygen


 

       a closed circuit  