(a) The promoter is a cis-acting site present physically continuous with transcription unit and provides a binding site for RNA polymerase enzyme. (b)Transfer RNAs (tRNAs) read the genetic information present in the form of triplets in the mRNA and transfer the appropriate amino acid from amino acid pool of cytoplasm to a growing polypeptide chain during protein synthesis.(c) Exons are the protein-coding sequences of RNA that serve to carry genetic information from DNA to proteins.