Which Nitrogenous base is absent in RNA?

Explanation-
The nitrogenous base that is absent in RNA is Thymine. It is replaced by the base Uracil in RNA. So, in RNA, the bases are Adenine, Guanine, Cytosine, and Uracil.
-Nitrogenous bases are the essential building blocks. They form the basic framework of nucleic acids, such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
-In DNA, there are four nitrogenous bases – Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). These building blocks pair up, referred to as base pairs, to create the twisted ladder-like structure of DNA, known as a double helix. Adenine and Thymine form a pair, as do Guanine and Cytosine.
-In RNA, Thymine is not present. RNA, unlike DNA, is usually a single-stranded structure, and its nitrogenous bases include Adenine (A), Uracil (U), Guanine (G), and Cytosine (C).
-Thymine of DNA is replaced by Uracil in RNA, so Adenine pairs with Uracil in the case of RNA.
-The reason for this change lies in the differing roles of DNA and RNA. DNA’s job is predominantly long-term storage of genetic information, shaping the identity, and functionalities of organisms. It needs to be stable, enduring, and precise.
-Thymine, chemically, is more stable compared to Uracil, and less likely to mutate.
-RNA has several roles but is best known for acting as a messenger, transferring genetic code from DNA to the ribosome, where proteins are synthesized. In RNA, Uracil replaces Thymine, likely because Uracil is energetically less expensive to produce.
-Thymine contains a methyl group (-CH3) functionally, which is not present in Uracil. This slight difference aids in the identification and protection of DNA in the cellular environment too.