Answer:
adenine/thymine/cytosine/guanine
Step-by-step explanation:
those are the base pairs that connect with each other to form the dna strings.
So a full dna string exists out of:
- a phosphate group
-a sugar group
- the nitrogen bases:(The four types of nitrogen bases found in nucleotides are: adenine (A), thymine (T), guanine (G) and cytosine (C). The order, or sequence, of these bases determines what biological instructions are contained in a strand of DNA)
the phosphate and sugar group link the bases together.