Out of 64 codons, 61 codons code for 20 types of amino acid, it is called:

Degeneracy of codons is the redundancy of the genetic code, exhibited as the multiplicity of three-base pair codon combinations that specify an amino acid. The exceptions are methionine (AUG) and tryptophan (UGG). Related Theory The genetic code is degenerate mainly at the third codon position. The degeneracy of the genetic code made it possible for organisms to prosper on Earth. Organisms, which did not use a degenerate genetic code, would extinguish from this planet. This is one significant point of the genetic code.