Final answer:
DNA molecules are comprised of long chains of nucleotides, which are the monomers that include a pentose sugar, a phosphate group, and a nitrogenous base.
Step-by-step explanation:
Molecules of DNA are composed of long chains of nucleotides. Each nucleotide consists of three components: a pentose sugar, a phosphate group, and one of four nitrogenous bases. In the context of DNA, these sugar molecules are deoxyribose. The sugars and phosphate groups create what is often referred to as the "backbone" of the DNA strand while the nitrogenous bases pair to form the rungs of the DNA double helix structure. This unique structure allows DNA to store genetic information that is used during cell division and protein synthesis. The nucleotides in DNA are adenine, cytosine, guanine, and thymine, which dictate the genetic code via their sequence.