Answer:
adenine (A, green), thymine (T, red), cytosine (C, orange), and guanine (G, blue).
Step-by-step explanation:
The nitrogen bases in a DNA molecule are adenine, guanine, cytosine, and thymine. Adenine and guanine belong to a class of compounds called purines, and cytosine and thymine belong to a class of compounds called pyrimidines. In a DNA molecule, the two strands are connecting by hydrogen bonds between the nitrogen bases of each strand. According to the base-pairing rule, the purine adenine always pairs with the pyrimidine thymine, and the purine guanine always pairs with the pyrimidine cytosine...