What system supplies the heat in a car?

The correct answer is the cooling system because it plays a critical role in regulating the temperature of the engine and can also provide heat to the vehicle's interior. In many vehicles, the cooling system includes components such as the radiator, water pump, and heater core, which works in conjunction with engine coolant to absorb heat from the engine and redistribute it through the vehicle. When the heating system is activated, coolant is directed through the heater core, effectively warming the air that is then blown into the cabin by the blower fan, thus providing heat to the occupants.

Other systems, such as the electrical, fuel, and exhaust systems, have distinct functions that do not directly contribute to heating the interior of the vehicle. The electrical system is primarily responsible for powering electrical components, the fuel system delivers fuel to the engine for combustion, and the exhaust system expels combustion gases. While they are crucial for the operation of the car, they do not supply heat; the cooling system specifically serves this purpose.