Question

Which nitrogenous bases are classified as pyrimidines?

Options

• Adenine and Guanine

• Thymine, Adenine, and Guanine

• Adenine, Guanine, and Cytosine

• Cytosine, Thymine, and Uracil

Answer 1

Cytosine, Thymine, and Uracil are the three pyrimidine bases, characterized by their single-ring structure. Cytosine is found in both DNA and RNA, thymine is found exclusively in DNA, and uracil is found exclusively in RNA. Pyrimidines are smaller than purines.