sentence2_structure: Carbon (c)<>is<>essential to living organisms<>because carbon bonds in many ways with itself to form chains$$$carbon bonds in many ways with itself<>to form<>chains
sentence1: The carbon atoms in these chains and rings can then form bonds with other elements in many ways to produce various functional groups.
sentence2: Carbon (c) is essential to living organisms because carbon bonds in many ways with itself to form chains.
question: What characteristic of carbon (C) makes it essential to living organisms?