Practice question

Question

A mutant strain of E.coli having defects in one of the DNA repair pathways was identified. To identify the pathways where mutation occurred, aresearcher looks at the following parameters and identified the defect to be in base excision repair pathway A. Topoisomerase 11 enzyme activity B. AP endonuclease activity c. Expression ot mutL and muts D. DNA glycosylase activity E. DNA ligase activity Based on the changes in which of the above parameters, this conclusion can be drawn?