What type of molecule that can be found in living things lacks carbon atoms

Water or H2O. The molecules involving water displays the absence of carbon atoms which is then disassembled primarily by cells thru the process of metabolism and then changed or mixed with other substances to form useful supply of cell activities. 
Proteins are from amino acids which has carbons in their composition. As well as carbohydrates and lipids

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1.fossils 2.analogous organs 3.homologous organs