What are the three specific types of rna?

rRNA, tRNA and mRNA are the three types of RNA where r, t and m stand for ribosomal, transfer and messenger respectively.

rRNA - which together with ribosomal proteins form ribosomes,

tRNA - translates the amino acids to the ribosomes

mRNA - encodes amino acid polypeptide

Hope it helped,

BioTeacher101

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.