Final answer:
Base excision DNA repair is a mechanism that corrects damage to a single nucleotide. It involves the removal of the damaged base and its replacement with the correct base.
Step-by-step explanation:
Base excision DNA repair is a type of DNA repair mechanism that corrects damage to a single nucleotide caused by oxidation, alkylation, hydrolysis, or deamination. This repair mechanism involves the removal of the damaged base by a specific enzyme called glycosylase. Once the damaged base is removed, it is replaced with the correct base through repair synthesis with DNA polymerase, and the gap is sealed with a phosphodiester linkage catalyzed by DNA ligase.