Which of the following is a basic structural unit of nucleic acids?

The basic structural unit of nucleic acids is the nucleotide. Nucleotides are the building blocks that make up nucleic acids, which include DNA and RNA. Each nucleotide consists of three components: a sugar molecule (either ribose in RNA or deoxyribose in DNA), a phosphate group, and a nitrogenous base (which can be adenine, thymine, cytosine, guanine for DNA, and uracil in the case of RNA). This specific arrangement allows nucleotides to link together through phosphodiester bonds, forming long chains that encode genetic information.

In contrast, RNA itself is a type of nucleic acid made up of many nucleotides, so it is not the basic unit but rather a polymer formed from them. A dipeptide is a term related to proteins, specifically a peptide made up of two amino acids linked by a peptide bond, which has no role in the structure of nucleic acids. Chlorophyll is a pigment found in plants responsible for photosynthesis and is unrelated to nucleic acid structure.