The Carbon Cycle - 0 views
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Gwen Noda on 06 Oct 10The Carbon Cycle What Goes Around Comes Around by John Arthur Harrison, Ph.D. Carbon is the fourth most abundant element in the universe, and is absolutely essential to life on earth. In fact, carbon constitutes the very definition of life, as its presence or absence helps define whether a molecule is considered to be organic or inorganic. Every organism on Earth needs carbon either for structure, energy, or, as in the case of humans, for both. Discounting water, you are about half carbon. Additionally, carbon is found in forms as diverse as the gas carbon dioxide (CO2), and in solids like limestone (CaCO3), wood, plastic, diamonds, and graphite.