The subunits of DNA are known as :

DNA (deoxyribonucleic acid) is a polymer composed of long chains of monomeric subunits called nucleotides [3]. Each nucleotide is the basic building block of nucleic acids and consists of three essential components: a five-carbon sugar (deoxyribose in DNA), a phosphate group, and a nitrogen-containing base [1]. The four nitrogenous bases found in DNA are adenine, guanine, cytosine, and thymine [3]. In contrast, a nucleoside consists only of the sugar and the base without the phosphate group [3]. A nucleosome is a higher-order structural unit where DNA wraps around histone proteins for packaging [4], and a polypeptide is a chain of amino acids that forms proteins. Therefore, the fundamental chemical subunits that repeat to form the DNA molecule are nucleotides [1].

Sources

1. [1] https://www.genome.gov/genetics-glossary/Nucleotide
2. [3] https://pmc.ncbi.nlm.nih.gov/articles/PMC6822018/
3. [2] https://www.cancer.gov/publications/dictionaries/genetics-dictionary/def/nucleotide
4. [4] https://www.sciencedirect.com/topics/medicine-and-dentistry/dna