Question

the gas that is not present in aircraft emissions is

carbon dioxide

sulfur dioxide

chlorine

oxygen

Explanation:

Aircraft burn fossil - fuels like jet fuel. Combustion of these fuels produces carbon dioxide and sulfur dioxide due to the presence of carbon and sulfur in the fuel. Chlorine can also be present in trace amounts from additives or impurities. Oxygen is a reactant in the combustion process and is not an emission product. It is consumed during the burning of fuel in the aircraft engines.

Answer:

D. oxygen