Carbon is essential for life because it bonds in many different ways to give rise to compounds that the body needs everyday. Every living organism contains carbon in some way or another. It is not found in a pure form in the human body, but in the form of compounds. Carbon constitutes roughly 18% of the total body mass, and carbon atoms form thousands of molecules in every cell. Carbon is the basic building block required for the formation of proteins, carbohydrates and fats which are required to maintain the normal physiology of the body.