What chemical compounds make up an RNA monomer?

The full name of the RNA molecule is ribonucleic acid. Polymer with a monomer called “nucleotide”. The latter consists of three parts:
bases of nitrogen;
pentose – the carbohydrate “ribose”. This type of carbohydrate determines the name of the nucleic acid;
part of the phosphoric acid molecule – Н2РО4.

There are four types of nitrogenous bases:
Adenine, abbreviated by the letter “A”;
Guanine – “G”;
Uracil – “U”;
Cytosine – “C”.
Bases are distinguished of two types: pyrimidine and purine. “Adenine”, “guanine” – purine, and pyrimidine – “cytosine”, “uracil”.