To which two molecules does transfer RNA attach

messenger RNA and amino acids.

Explanation: A transfer RNA (tRNA) is a type of RNA whose function is to fetch and match the corresponding amino acid to the codon on the mRNA during translation. A tRNA has a three nucleotide sequence known as anticodon through which it attaches to the codon on the mRNA molecule. During translation, the codons on the mRNA molecule is read one after another by the ribosome while the tRNA attaches itself to the mRNA codon that is being read through its anticodon. The tRNA then fetches the corresponding amino acid from the cytosol and attaches it to the growing polypeptide chain.