Answer:
Determined that the chemical in cigarette smoke is an oxidant.
Step-by-step explanation:
Basically, an oxidant is a reactant that oxidizes or removes electrons from other reactants during a redox reaction. What the medical researcher is trying to do is looking at each element's oxidation state before and after the reactant and then preventing the damage by adding vitamin E to the mixture, therefore determining that cigarette smoke is an oxidant.