Which statement correctly describes adenine's pairing and classification?

Which statement correctly describes adenine's pairing and classification?

• A. A ribose sugar
• B. The base that pairs with Thymine in DNA. It's a purine.
• C. A base that pairs with Cytosine
• D. A pyrimidine

Answer: (B)

Adenine is a nitrogenous base classified as a purine, which means it has two rings. In DNA, adenine pairs specifically with thymine through two hydrogen bonds, forming the A–T pair. This pairing fits the broader rule that purines pair with pyrimidines (purine with pyrimidine). So describing adenine as the base that pairs with thymine in DNA and noting that it is a purine correctly captures both its pairing and its classification. It isn’t a sugar (the sugar is deoxyribose in the backbone), it doesn’t pair with cytosine (that’s guanine), and it isn’t a pyrimidine (that group includes cytosine, thymine, and uracil).

Adenine is a nitrogenous base classified as a purine, which means it has two rings. In DNA, adenine pairs specifically with thymine through two hydrogen bonds, forming the A–T pair. This pairing fits the broader rule that purines pair with pyrimidines (purine with pyrimidine). So describing adenine as the base that pairs with thymine in DNA and noting that it is a purine correctly captures both its pairing and its classification. It isn’t a sugar (the sugar is deoxyribose in the backbone), it doesn’t pair with cytosine (that’s guanine), and it isn’t a pyrimidine (that group includes cytosine, thymine, and uracil).