lung cancer mortality, cumulative risk (%) 15 10 45 55 Figure 20-3 MBOC6: The Problems Book (O Garland Science 2015) 65 age (years) 75 never stopped stopped □age 30 stopped age 50 never smoked 85 Based on the data in the figure above, the biological basis for substantially reduced risk of lung cancer from stopping smoking is a return to an average mutation rate for the remainder of their life. an increase in the number of changes required for cancer. the protective effects of smoking briefly while young. stimulation of DNA repair mechanisms in former smokers. the reversal of mutations after quitting.

lung cancer mortality, cumulative risk (%) 15 10 45 55 Figure 20-3 MBOC6: The Problems Book (O Garland Science 2015) 65 age (years) 75 never stopped stopped □age 30 stopped age 50 never smoked 85 Based on the data in the figure above, the biological basis for substantially reduced risk of lung cancer from stopping smoking is a return to an average mutation rate for the remainder of their life. an increase in the number of changes required for cancer. the protective effects of smoking briefly while young. stimulation of DNA repair mechanisms in former smokers. the reversal of mutations after quitting.