Which of the following statements are correct for genetic code?

(i) George Gamow, first reported that the code should be made up of three nucelotides.

(ii) Har Gobind Khorana developed chemical method for synthesizing RNA molecules with defined combinations of bases (homopolymers and co-polymers.)

(iii) Nirenberg developed cell-free system for protein synthesis which finally helped in decoding of codons.

(iv) Ochoa discovered enzyme polynucleotide phosphorylase which helpful in polymerishing RNA with defined sequences (enzymatic synthesis of RNA).

(v) One codon codes for many amino acids, hence, it is unambiguous and specific.

(vi) Some amino acids are coded by only one codon, hence the code is degenerate.

(vii) AUG has dual functions, it codes for Methionine and it also act as initiator codon.