If a carbon atom is bonded to two hydrogen atoms and two carbon atoms, what type of bond must exist between the carbon atoms?

A double bond must exist between two carbon atoms if bonded to two hydrogen atoms. This is because the two carbon atoms share electrons and are in itself a covalent bond. Because they are bonding to the hydrogen atoms it is a double bond.I hope that my answer is helpful! Let me know if you need something more :)

The basic repeating unit of nucleic acids are known as nucleotides. a nucleotide consists of three distinct chemical groups.