Question

It has a double ring. *
uracil
guanine
cytosine
Other:​

Answer 1

Explanation:

Because of their structural similarity, we usually refer the nine-member double rings adenine and guanine as purines, and six-member single-ring thymine, uracil, and cytosine are pyrimidines. Fig. 1.5. (A) Chemical structure of pyrimidines and purines nitrogenous bases in DNA and RNA.

Answer 2

in the given nucleic acids, guanine has a double ring structure.(since it is a purine)

Explanation:

among nucleic acids, purines(adenine, guanine) have a double ring structure; whereas pyramidines(thyamine/uracil, cytosine) have a single ring structure.