1. The problem asks to identify the types of current supplied by batteries and mains electricity. 2. The current supplied by batteries is called **direct current (DC)** because it flows in one direction only. 3. The current supplied by mains electricity is called **alternating current (AC)** because it periodically reverses direction. 4. To summarize: - Batteries provide **direct current (DC)**. - Mains electricity provides **alternating current (AC)**. This distinction is important in understanding how electrical devices are powered and how current behaves in circuits.