What characteristic describes direct current (DC) in electrical terms?

Direct current (DC) is characterized by its ability to maintain a constant flow of electric charge in a single direction. This means that the voltage remains steady over time, without the oscillations seen in alternating current (AC). This consistent flow makes DC ideal for various applications, especially in digital electronics, batteries, and solar energy systems where stable and reliable power is essential.

While it is true that DC can be converted into alternating current through devices such as inverters, the fundamental characteristic of DC itself is that it flows unidirectionally and does not change polarity. Options that refer to its use strictly in batteries and solar systems are too narrow, as DC also powers a wide range of electrical devices and systems beyond these applications. Therefore, describing DC as remaining constant and flowing in one direction captures its essential nature in electrical terms.