Which of the following nucleotide bases is found only in RNA, not in DNA? - Biology (Theory)

Uracil

Explanation:

In the structure of nucleic acids, Uracil is the unique nitrogenous base that is exclusively found in RNA, where it serves as a replacement for Thymine found in DNA. While both DNA and RNA share three common bases, Adenine, Guanine, and Cytosine, the presence of Uracil instead of Thymine is one of the primary chemical differences between these two molecules. During the process of protein synthesis, Uracil follows specific pairing rules by forming two hydrogen bonds with Adenine, similar to how Thymine pairs with Adenine in the DNA double helix.