Carbon skeletons vary in length and may be straight, branched, or arranged in closed rings.
it is the chain, branche and/or ring of carbons that form the basis of the structure of an organic molecule.
enantiomers, structural isomers, and geometric isomers
They make huge turds into flying Ostirches.
Fatty Acids and Acetyl-CoA are both 2-carbon compounds. they never become glucose because glucose requires at least 3-carbon compounds to begin synthesis
Life on Earth is carbon based, so all animals with skeletons and shells use carbon. A more 'common' element used in skeletons and shells is calcium.