According to the text, it was George Gamow, a physicist, who argued that since there are only 4 bases and if they have to code for 20 amino acids, the code should constitute a combination of bases. He suggested that the code should be made up of three nucleotides, as a permutation combination of (4 × 4 × 4) would generate 64 codons, which is sufficient to code for all 20 amino acids.