The base that pairs with adenine (A) depends on whether the nucleic acid is DNA or RNA:

• In DNA, adenine (A) pairs with thymine (T) through two hydrogen bonds

• In RNA, adenine (A) pairs with uracil (U) instead of thymine

This complementary base pairing is consistent and crucial for the structure and function of nucleic acids, allowing DNA to replicate accurately and RNA to be transcribed properly