How does an alternator differ from a battery in a vehicle?

The correct choice illustrates the fundamental roles of the alternator and the battery within a vehicle's electrical system. The alternator is primarily responsible for generating electrical energy while the engine is running. It converts mechanical energy from the engine into electrical energy, which is then used to power the vehicle's electrical accessories and recharge the battery.

In contrast, the battery serves a different purpose; it stores electrical energy that is used to start the engine and supply power to electrical components when the engine is off. The distinction between generating and storing energy is crucial for understanding the function of these two components within the vehicle's electrical system. This differentiation is important because it highlights how the alternator and battery work together to ensure that the vehicle operates efficiently under various conditions.