Answer:
Argon gas
Step-by-step explanation:
Argon is a chemical element. Its symbol is Ar. It is the noble gas which is odorless and colorless. It is one of the most abundant gas on the earth after oxygen and nitrogen.
Argon gas is most commonly used in the panes of the thermal windows. It has 34 percent lower thermal conductivity as compared to the air and so it is more comfortable to used instead of the air. It is an inert gas and does not react with other things. It is not harmful.