Answer:
4 nucleotides.
Step-by-step explanation:
Basic building block of DNA is known as nucleotides, and they are composed of one phosphate molecule, a sugar, and four bases (guanine, adenine, cytosine, and thymine).
Purine bases is adenine and guanine they contain double ring structure, and pyrimidine bases is cytosine, and thymine they contain single ring structure. The nucleotide bases of DNA line up together, so that the phosphate, and sugar molecule make two long backbones, and each strands of DNA.