Final answer:
Nucleotide excision repair (NER) is the term for the repair mechanism that recognizes gross distortions in the helical DNA structure.B) Nucleotide excision repair (NER)
Step-by-step explanation:
The repair mechanism that recognizes gross distortions in the helical DNA structure is Nucleotide excision repair (NER). NER repairs damage affecting longer strands of 2-30 bases and recognizes bulky, helix-distorting changes such as thymine dimers as well as single-strand breaks. A specialized form of NER known as Transcription-Coupled Repair (TCR) deploys high-priority NER repair enzymes to actively transcribed genes.