Question: what is an amino acid that has more than one codon?
Answer: Redundancy in the genetic code means that most amino acids are specified by more than one mRNA codon. For example, the amino acid phenylalanine (Phe) is specified by the codons UUU and UUC, and the amino acid leucine (Leu) is specified by the codons CUU, CUC, CUA, and CUG.