Answer:
Mutations are errors in codons caused by changes in nucleotide bases. Some mutations may not have much effect. For example, if the codon GAA becomes the codon GAG, because the genetic code is degenerate, the codon will still code for the amino acid glutamate. Such ineffectual mutations are called silent mutations. Some mutations, however, can have a huge affect on coding for amino acids, which can in turn affect what proteins are produced, which can have a profound effect on cellular and organismal function.