Q: What is CO2?

A: Carbon dioxide (CO2) is a gas composed of one atom of carbon and two atoms of oxygen. CO2 occurs naturally in the atmosphere, is essential to plant life and, as a greenhouse gas (GHG), helps create the greenhouse effect that keeps our planet livable. CO2 is exhaled by humans and is used to put the bubbles in
 soft drinks, as a coolant (dry ice), and in fire extinguishers.