Which of the following best describes engine displacement?

Engine displacement is best described as the total volume inside the cylinders of an engine. This measurement is crucial because it directly influences the engine's ability to intake air and fuel for combustion, which in turn affects the power output and efficiency of the engine. Displacement is typically measured in liters or cubic centimeters (cc) and is calculated based on the size and number of cylinders in the engine.

Understanding engine displacement is important since it helps indicate the engine's potential for producing power. A larger displacement usually means that an engine can produce more power, as it can burn more fuel and air mixture during each cycle.

Other choices focus on different aspects of engine operation. The volume of air needed for combustion relates to the air-fuel ratio but does not encompass the total volume within the engine's cylinders. The distance an engine can travel pertains to mileage or fuel efficiency, while the pressure exerted by the engine refers to performance metrics like boost in turbocharged engines but does not define displacement itself.