Which of the following statements best describes the combustion section of a turbofan engine?

The combustion section of a turbofan engine is critical in the process of generating thrust. It functions by mixing air that has been compressed by the compressor with fuel, which is then ignited. This controlled combustion process produces high-temperature and high-pressure exhaust gases that expand and are expelled through the turbine and exhaust nozzle, ultimately generating thrust.

This statement effectively captures the primary role of the combustion section in that it not only highlights the importance of mixing air and fuel but also emphasizes the ignition process needed for combustion to occur. The gases resulting from this combustion provide the energy necessary to power the turbine and contribute to the engine’s overall efficiency and thrust output.

In contrast, the other options do not accurately represent the function of the combustion section. The combustion section does not solely add fuel before the turbine or compress air before injecting fuel; these actions occur in different sections of the engine. Additionally, the combustion section does not expel exhaust gases without mixing, as the process of combustion is integral for producing the exhaust gas that drives the engine's mechanics.