A characteristic of direct current is that it?

Direct current (DC) is defined by the fact that it travels only in one direction. This characteristic is key to understanding how DC differs from alternating current (AC), which periodically changes direction. In practical applications, this unidirectional flow enables DC to be used in devices such as batteries and electronic circuits where a stable and consistent voltage is required.

The other options relate to characteristics of AC or concepts not applicable to DC. For instance, the notion of requiring an inverter pertains to the conversion of DC to AC rather than a property of DC itself. Therefore, the accuracy of the definition highlighting that direct current flows solely in one direction directly underlines the distinctive nature of this type of current.