Which nitrogenous base is found in RNA but not in DNA?

In RNA, the nitrogenous base uracil is present instead of thymine, which is found in DNA. Uracil pairs with adenine during RNA synthesis, similar to how thymine pairs with adenine in DNA. This distinction is significant because it illustrates one of the fundamental differences between the structures of DNA and RNA. While both DNA and RNA contain adenine, cytosine, and guanine, the unique presence of uracil in RNA and the absence of thymine highlight the key variations in their composition and function. This difference is crucial for various biological processes, including the transcription of genetic information and the formation of different types of RNA necessary for protein synthesis.