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These are two of the reasons why carbon is the versatile element that is the basis of life on earth.
What is how it can form either 1.) chains (straight or branched), it can form rings, 2.) single or double bonds, 3.) can associate with a wide variety of other elements, 4.) can store a lot of energy in the bonds with other elements, 5.) is the smallest (most agile) of the tetravalent elements.