Which nitrogenous base pairs with adenine in DNA?

In DNA, adenine pairs specifically with thymine through the formation of two hydrogen bonds. This pairing is crucial for the stability of the DNA double helix structure, as it allows for the complementary base pairing that maintains the genetic code. The structural similarities between adenine and thymine, both being purines and pyrimidines respectively, facilitate this hydrogen bonding, ensuring accurate replication and transcription processes.

In contrast, the other nitrogenous bases have different pairing rules: cytosine pairs with guanine, and uracil is found in RNA, where it pairs with adenine, not in DNA. Understanding these base pairing rules is fundamental to grasping how genetic information is stored and transmitted in living organisms.