Explain how mutagens can cause genetic mutations in spite of your body's dna repair enzymes

Primarily: "a lethal illness can be caused by the malfunction of just one type of enzyme out of the thousands of types present in our bodies." 

A. Mutagens can over power the enzymes like cancer does with wild growth. 
B. Mutagens infect a mutation that the body and its enzymes don't react to, it may be too subtle. 
C. The enzymes themselves can cause genetic diseases if they are found in concentrations that are too high or too low. 
D. The enzymes can be affected by temperature or other activities, like the pH value and the chemicals around it. In case of anemia or when the pH value is slightly off or under other circumstances the enzyme can be inhibited from acting. 
E. Chemicals called inhibitors exist that can slow down or stop the action of enzymes, many of these are poisons. 
F. The enzymes themselves can malfunction by a genetic mutation. This is just one way that cancer can attack the body.