A circuit with a source of energy and at least one conductor is called a simple circuit.

Here's why:

* Source of energy: Provides the electrical potential difference (voltage) that drives the flow of electrons. This could be a battery, a generator, or a power supply.

* Conductor: A material that allows electrons to flow easily through it. Examples include wires, metal strips, and conductive liquids.

Together, these components create a closed loop where electrons can flow from the source, through the conductor, and back to the source, completing the circuit.