What is defined as a closed loop allowing current to flow?

An electrical circuit is characterized as a closed loop that enables current to flow. This definition is critical to understanding basic electrical principles, as a circuit must be complete for current to circulate. An electrical circuit typically consists of various components, including power sources, loads, conductors, and sometimes switches, all arranged to facilitate this flow of electricity.

In the context of the question, a power source refers to the origin of electrical energy, such as a battery or generator, but it alone does not define the closed loop necessary for current to flow. A resistor is a component that limits or regulates the flow of current within a circuit but does not define the circuit itself. An electrical load, such as a light bulb or an appliance, consumes electrical energy but is also not sufficient on its own to represent the concept of a closed loop. Therefore, the term "electrical circuit" distinctly encompasses the entire system required for current flow, making it the correct answer in this context.