Final answer:
The phrase 'codons are redundant' means that most amino acids are specified by more than one particular codon due to the degeneracy of the genetic code, which helps reduce the impact of mutations.
Step-by-step explanation:
The statement "codons are redundant" refers to the fact that most amino acids are specified by more than one codon. This aspect of the genetic code is known as degeneracy and ensures a reduced impact of random mutations on protein function. For example, the amino acid threonine is encoded by the codons ACU, ACC, ACA, and ACG. Degeneracy usually occurs at the third nucleotide position of a codon, which is less important for specifying an amino acid and thus allows for some variability without affecting the overall structure and function of the protein.