Which of these is a function of a ribosome?

Ribosomal units can decode the codons on mRNA and assemble amino acids with the help of tRNA for translation. Codons are contained within the mRNA strand, not on or inside the ribosomes. Ribosomes do not move along the length of an amino acid chain, they create one. They move along the mRNA strand to decode it, which then directs the formation of the complementary amino acid chain. The transfer of mRNA from the nucleus to the cytoplasm does not occur with the help of tRNA.