Answer:
Nucleotides
Step-by-step explanation:
DNA is made of chemical building blocks called nucleotides. These building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases. To form a strand of DNA, nucleotides are linked into chains, with the phosphate and sugar groups alternating. And he four types of nitrogen bases found in nucleotides are: adenine (A), thymine (T), guanine (G) and cytosine (C).