Mutation would be the best answer.
First one, disease causing microorganisms
<span>c. regular exercise has little impact on maintaining peak performance after age 30</span>
<span>More than 50</span>. There are more than 7000 chemicals in cigarette smoke, 250 of which are known to be detrimental to health and 69 chemicals are carcinogenic (can cause cancer). Some of the carcinogenic chemicals in cigarette smoke are: Arsenic, Cadmium, Chromium, Formaldehyde and Nickel.
