Which two components primarily compose the engine's propulsion system?

The propulsion system of an engine is primarily composed of the power turbine section and the gas generator section. The gas generator section is responsible for the initial process of air intake, compression, and combustion. In this section, air is compressed and then mixed with fuel to facilitate combustion, resulting in high-pressure, high-temperature gases.

These gases then flow into the power turbine section, where they expand and create the thrust necessary for propulsion. This section converts the energy from the high-speed gases into mechanical power, which drives the engine and provides thrust. Together, these two sections work in tandem to efficiently produce power and propel the aircraft.

The other options focus on different components of an engine that contribute to its overall function but do not directly represent the primary components of the propulsion system. For example, the power section and cooling section refer to aspects of engine performance but do not encompass the propulsion mechanism itself. Similarly, while the fuel section is critical for combustion, it is part of the gas generator. The compressor and combustion sections are parts of the gas generator but do not constitute the entire propulsion system, which includes both the gas generator and the power turbine sections.