Final answer:
The nonspecific repair mechanism where damaged DNA is removed and replaced is excision repair, specifically nucleotide excision repair, which addresses issues like pyrimidine dimers caused by UV exposure.
Step-by-step explanation:
The type of nonspecific repair mechanism in which a damaged region of DNA is removed and then replaced by DNA synthesis is known as excision repair. Specifically, nucleotide excision repair is employed when DNA damage such as pyrimidine dimers occurs. This type of damage often results from UV exposure. Enzymes make cuts on both the 3' and 5' ends of the damaged base to remove the defective segment. DNA polymerase then adds the correctly paired nucleotides, and DNA ligase seals the gap with a phosphodiester bond.