Carbon Cycle Chemical Reactions Involved: Photosynthesis: Air and water molecules and the energy from the sun to produce a simple sugar such as glucose and oxygen molecules as a by product. During photosynthesis plants use carbon dioxide and produce oxygen.
Similar to shore power for ships, a ground power unit (GPU) may be used to supply electric power for an aircraft on the ground, to sustain interior lighting, ventilation and other requirements before starting of the main engines or the aircraft auxiliary power unit (APU).
Auxillary Power Unit (APU) and Ground Power Unit (GPU) is used to mostly to assist the aircraft engines to start. They supply air to Air driven Motor. The motor is mechanically connected to the high pressure compressor assembly of the engine. This starts the engines.