Do you some amino acids have more than one mRNA codon?

Most amino acids are indicated by more than one codon.

Explanation: Because there are only 20 different amino acids but 64 possible codons, most amino acids are indicated by more than one codon so the essential amino acids are coded by more than one codon, so that mutation does not change the amino acid sequence in the peptide chain.

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.