Oxidation-Reduction (REDOX) reactions can be defined with respect to electrons and Hydrogen and Oxygen.
Electrons:
In a reaction the atom which looses electron(s) is said to be oxidized (reducing agent) and the atom which gains electron(s) is said to be reduced (oxidizing agent).
Oxygen-Hydrogen:
In a reaction if a reactant looses hydrogen or gain oxygen is said to be oxidized and the reactant which looses oxygen and gains hydrogen is said to be reduced.
Result:
The correct answer is "May involve in loss of Hydrogen and Electrons".
