Non-constituitive system with visible light energy breaking covalent t-t bonds multiple enzymes may repair an a-c error left unrecognized by dna polymerase catastrophic dna damage caused by ultraviolet light can be survived by the cell with this a "spell check" function by the normal replication enzyme to ensure fidelity thymine dimer-containing section of dna is cut out, resynthesized and sealed
a. proofreading
b. photoreactivation
c. mismatch repair
d. sos repair
e. excision repair