The Correct answer is All of the above. • Oxidation-reduction reaction, also called redox reaction, any chemical reaction in which the oxidation number of a participating chemical species changes. The term covers a large and diverse body of processes. Many oxidation-reduction reactions are as common and familiar as fire, the rusting and dissolution of metals, the browning of fruit, and respiration and photosynthesis - basic life functions. • Most oxidation-reduction (redox) processes involve the transfer of oxygen atoms, hydrogen atoms, or electrons, with all three processes sharing two important characteristics: • They have coupled i.e.in any oxidation reaction a reciprocal reduction occurs. • They involve a characteristic net chemical change i.e., an atom or electron goes from one unit of matter to another. Both reciprocity and net change are illustrated below in examples of the three most common types of oxidation-reduction reactions. • In the above reactions, all of the changes occurring that is the transfer of oxygen atoms, hydrogen atoms, or electrons.