Answer:
The genetic code is degenerate because codon sequences, i.e., consecutive three nucleotides in the mRNA sequence, may exhibit variation among them and encode the same aminoacid.
Explanation:
In this case, the four species encode mRNAs that are translated into homologous proteins. These homolog proteins share sequence identity as they are evolutionary (and structurally) related. However, mRNAs are different because genomic sequences accumulate variation during evolution