What is true about direct current (DC)?

Direct current (DC) is characterized by its flow of electric charge in a single direction, which distinguishes it from alternating current (AC), where the flow periodically reverses direction. This unidirectional flow means that the voltage remains constant over time, although it can vary in terms of magnitude depending on the source or system conditions.

Batteries are a common source of DC, as they produce a steady and consistent voltage output that drives current in one direction. Other sources of DC include solar cells and certain types of generators that are designed to produce direct current.

The choice that encompasses all these attributes confirms that direct current is indeed produced by batteries, flows in one direction, and can vary in magnitude, depending on the source or circuit. This comprehensive understanding is key when working with electrical systems that utilize DC.