Question

Which nucleotides have a double ring structure?

1) uracil and thymine
2) cytosine and guanine
3) adenine and guanine
4) adenine and thymine

Answer 1

Adenine and guanine nucleotides have a double ring structure and are classified as purines, while cytosine, thymine, and uracil nucleotides have a single ring structure and are classified as pyrimidines.

Step-by-step explanation:

The nucleotides adenine and guanine have a double ring structure and are classified as purines, while the nucleotides cytosine, thymine, and uracil have a single ring structure and are classified as pyrimidines.