Carbon is found in all organic molecules in the human body, which includes fats, carbohydrates, nucleic acids, and proteins. Carbon is also found in CO2 (carbon dioxide), a waste product of the body that is exhaled through the lungs.
Carbon is the second most abundant element in the human body's chemical composition, second only to oxygen. In addition to being a fundamental building block of most of the body's cellular structures, carbon is present in the blood as dissolved carbon dioxide, carbonic acid and bicarbonates. In this role, carbon is regulator of the body's pH, the cardiovascular system, and plays a role in the proper functioning of the digestive system.