A colorless, odorless, nonpoisonous gas that is a normal part of the air. Carbon dioxide, also called CO2, is exhaled by humans and animals and is absorbed by green growing things and by the sea
United States Department of Agriculture USDA, Glossary of Terms, Washington, DC, USA 2014. http://www.usda.gov/energy/matrix/FindTerms, (Oil - Amer) {780}