A gas present in air, produced in combustion,
fermentation and animal metabolism. Carbon dioxide is produced when
any form of carbon or almost any carbon compound is burned in an excess
of oxygen. In animal respiration carbon dioxide combines with haemoglobin
in red blood cells, is carried to the lungs and is breathed out. Green
vegetation uses chlorophyll to combine carbon dioxide with hydrogen
to form carbohydrates (photosynthesis).
Typical products include fizzy drinks,
carton fruit juice, wine.