Which components are essential in an aircraft's fuel system?

The components that are essential in an aircraft's fuel system are fuel tanks, lines, and filters. Fuel tanks are where the aircraft's fuel is stored, and they are designed to ensure safe and efficient fuel containment. The lines are critical for transporting the fuel from the tanks to the engine, ensuring that the fuel system functions effectively and efficiently. Filters are necessary to remove impurities and contaminants from the fuel, preventing them from reaching the engine and causing damage or inefficient performance. Together, these components play a vital role in ensuring that the aircraft has a reliable and safe fuel supply, which is essential for flight operations.

The other options, while important in their respective systems, do not pertain to the fuel system specifically. Wings, engines, and propellers relate to the aircraft's structure and propulsion system; the control surfaces such as elevators, rudders, and ailerons are essential for maneuverability; and electrical systems, seats, and landing gear are associated with the overall aircraft functionality but do not pertain to the fuel system.