What job does the water pump perform in the cooling system?

The water pump plays a crucial role in the engine's cooling system by circulating coolant throughout the engine. This coolant absorbs heat produced during combustion and helps maintain optimal operating temperatures. As the coolant circulates, it passes through the radiator where it sheds heat to the atmosphere, allowing the engine to stay within a safe temperature range. By continuously moving coolant, the water pump ensures that all parts of the engine receive adequate cooling, preventing overheating and potential damage.

The other options relate to different functions within an engine: mixing fuel and air is a task performed by the carburetor or fuel injectors; injecting fuel into the air stream is also relevant to fuel injectors; and regulating engine speed pertains to the throttle system.