Choose the words to finish the sentence

A strand of DNA is a polymer of Choose ... joins by covalent bonds between the Choose ... of one monomer and the Choose ... of the next monomer

A strand ... = nucleotides or nitrogenous bases?

Joins by covalent ... = deoxyribose, thymine, adenine, or guanine

Of one monomer ... = phosphate group or nitrogenous base

Answer: A strand of DNA is a polymer of nucleotides joins by covalent bonds between the deoxyribose of one monomer and the phosphate group of the next monomer.

Explanation: Nucleotides are the building blocks or monomeric units of DNA. Nucleotides have three components: A nitrogenous base, a pentose and a phosphate group. Nucleotides have two kinds of pentoses: deoxyribose and ribose but only deoxyribose is found in DNA. The nitrogenous bases are derivatives of two parent compounds pyrimidine and purine. The two major purine bases are adenine and guanine while the pyrimidine found in DNA are cytosine and thymine. The successive nucleotides of DNA are covalently linked through phosphate group bridges in which the 3'-hydroxyl group of one nucleotide unit is joined to the 5'-phosphate group of the next nucleotide by a phosphodiester linkage.