Short answers, pulled from the story.
Redox chemistry is a type of chemical reaction in which the oxidation states of the reactants change. This process involves the simultaneous occurrence of oxidation and reduction where electrons are transferred between species.
The term redox first appeared in a 1928 article written by Leonor Michaelis and Louis B. Flexner. They combined separate words for oxidation and reduction to describe the simultaneous nature of these opposing changes.
Oxidizing agents accept electrons and are themselves reduced, while reducing agents donate electrons and are themselves oxidized. Substances that lose electrons act as reducing agents and substances gaining electrons serve as oxidizing agents.
Antoine Lavoisier demonstrated that the original meaning of reduction referred to the loss in weight upon heating a metallic ore such as a metal oxide to extract the metal. This weight loss occurred due to the loss of oxygen as a gas.
Rusting forms when oxygen combines with other elements to create hydrated iron oxides like Fe2O3 dot nH2O. This electrochemical oxidation of metals occurs in reaction with an oxidant such as oxygen.