Answer:
substitution
Explanation:
A substitution is a point mutation where a nucleotide base (either adenine, guanine, thymine or cytosine) is replaced by a different base pair. In contrast to insertions or deletions, substitutions don't change the number of bases in the DNA sequence. Moreover, inversions are large genetic rearrangements where the genetic sequence is reversed. A substitution may have different effects: change a codon to another (changing the protein sequence when codons are translated into amino acids), produce a stop codon, cause synonymous mutations (i.e., neutral mutations that don't alter the amino acid sequence due to the degeneracy of the genetic code), etc.
