Carbon dioxide is a colorless gas occurring naturally in Earth's atmosphere. Carbon dioxide is a primary carbon source for life on Earth. It is produced by all aerobic organisms during metabolism of carbohydrates and lipids. Carbon dioxide is used in food industry as an acidity regulator and for production of carbonated soft drinks and soda water. In medicine, carbon dioxide is commonly used as an insufflation gas for minimally invasive surgery (laparoscopy, endoscopy, and arthroscopy) to enlarge and stabilize body cavities to provide better visibility of the surgical area. A mixture of carbon dioxide and oxygen is used for stimulation of breathing after apnea, in anesthetic procedures to increase the depth of respiration, to facilitate blind intubations in anesthetic practice.