Final answer:
Neutral mutations are mutations that result in the use of a chemically similar, but different, amino acid. These mutations have no significant effects on an organism's survival or reproduction.
Step-by-step explanation:
Neutral mutations are mutations that occur in an amino acid codon and result in the use of a different, but chemically similar, amino acid. These mutations are similar to silent mutations, where a codon mutation may still encode the same amino acid. For example, a change from CCA to CCU will still encode proline, so no discernible change occurs. Neutral mutations have no significant effect on the organism's survival or reproduction.