Thermal windows often have all the air pumped out between the panes and a gas pumped in that is not harmful and won't react with other things. what gas would be used? a. o b. cl c. ar d. n

C. ar or argon

it is the most commonly used gas between thermal  window panes. argon has 34% lower thermal  conductivity than air and is therefore more suitable to be used instead of air. it is also inert and does not react or causes any form of harm