Which component turns off the circuit?

An open switch is the component that turns off the circuit. When a switch is open, it breaks the conductive path through which the electric current can flow, effectively stopping the flow of electricity. This lack of current flow means that any devices powered by that circuit will not operate, as they require a closed loop to function properly.

In contrast, a closed switch allows electricity to flow freely through the circuit. A battery serves as a source of electrical energy, supplying power to the circuit, while a resistor affects the flow of current but does not turn off the circuit by itself. These components work together to control and manage the circuit's operation, but only an open switch specifically interrupts the current flow.