Final answer:
In eukaryotic nucleotide excision repair, XPC recognizes helix distortions such as thymine dimers, similar to the role of UvrA in bacteria.
Step-by-step explanation:
In eukaryotic nucleotide excision repair (NER), the protein XPC plays a critical role similar to that of UvrA in bacteria. The primary function of XPC within this repair mechanism is to recognize distortions in the DNA helix, like those caused by thymine dimers. This recognition of helix-distorting lesions is crucial for the repair process, as XPC initiates the repair by locating the damage so that the appropriate NER machinery can then excise the damaged strand. This is vital for maintaining genomic integrity and preventing mutations from being fixed into the genome. The correct answer to your question is (a) Recognizes distortion like UvrA does.