Oxidation and reduction are chemical processes that involve the transfer of electrons between substances. Oxidation refers to the loss of electrons, which often results in an increase in the oxidation state of an element. For example, when iron reacts with oxygen, iron loses electrons and becomes oxidized, forming rust. In contrast, reduction is the gain of electrons, leading to a decrease in the oxidation state. During the same reaction, oxygen gains electrons and is reduced. Together, these processes are known as redox reactions, and they are fundamental to many chemical reactions, including those in biological systems and energy production.