Enzymes that assist in the repair of deoxyribonucleic acid (DNA) defects by recognizing the defect, cleaving the abnormal chain, and then removing the distorted regions are known as

Endonucleases

Explanation:

Endonucleases are involved in DNA repair. The repair can be a base-excision repair, nucleotide excision repair or mismatch repair.

Endonucleases are of different types and the type that will involve in DNA repaid depends on the type of repair that is required. It include deoxyribonuclease I and restriction endonuclease/restriction enzymes. The former cleaves DNA without taking note of the nucleotide sequence while the later is specific in the sequence of nucleotides it cuts.