Answer:
RNA is a single-stranded nucleic acid that is composed of three main elements: a nitrogenous base, a five-carbon sugar and a phosphate group. Messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA) are the three major types of RNA.
Ribonucleic acid (RNA) is a molecule similar to DNA. Unlike DNA, RNA is single-stranded. An RNA strand has a backbone made of alternating sugar (ribose) and phosphate groups. Attached to each sugar is one of four bases--adenine (A), uracil (U), cytosine (C), or guanine (G).
RNA consists of ribose nucleotides (nitrogenous bases appended to a ribose sugar) attached by phosphodiester bonds, forming strands of varying lengths. The nitrogenous bases in RNA are adenine, guanine, cytosine, and uracil, which replaces thymine in DNA.
