Question

there are ____ nitrogen bases in dna.
4
3
2
question 7
1 pts
match the purines and the pyrimidines to their correct nitrogenous base.
adenine and guanine
choose
thymine and cytosine
choose

Explanation:

DNA has four nitrogen bases: adenine (A), thymine (T), cytosine (C), and guanine (G). Purines are double - ringed structures, and adenine and guanine are purines. Pyrimidines are single - ringed structures, and thymine and cytosine are pyrimidines.

Answer:

For the first question: 4.
For the matching: Adenine and Guanine - Purines; Thymine and Cytosine - Pyrimidines.