Which nitrogenous base pairs with thymine in DNA?

In DNA, the nitrogenous base that pairs with thymine is adenine. This pairing occurs through the formation of hydrogen bonds, with adenine forming two hydrogen bonds with thymine, which is a key aspect of the double-helix structure of DNA. This specific base pairing is often referred to as complementary base pairing, where adenine (A) complements thymine (T), stabilizing the DNA structure and allowing for accurate replication and transcription processes.

Cytosine and guanine are also nitrogenous bases found in DNA, but they pair with each other rather than with thymine. Uracil, while it is a nitrogenous base in RNA, does not appear in DNA, as it replaces thymine in RNA structures. Thus, adenine is the only correct choice that pairs with thymine in the context of DNA.