Final answer:
RNA is a chain of nucleotides, which are composed of a nitrogenous base, ribose sugar, and a phosphate group.
Step-by-step explanation:
Ribonucleic acid, or RNA, is a molecule that is crucial in various biological roles, primarily in the process of protein synthesis. RNA is composed of monomers called nucleotides, and not proteins, amino acids, or monosaccharides. Each nucleotide includes a nitrogenous base, a pentose sugar known as ribose, and a phosphate group. These nucleotides are linked together by phosphodiester bonds to form a single-stranded RNA molecule. The nitrogenous bases in RNA are adenine (A), cytosine (C), guanine (G), and uracil (U).