Redox reactions are composed of two parts; reduction and oxidation. Reduction is the gain of electrons by an atom. Oxidation is the loss of electrons by an atom. Organic fuel substances can be oxidized. While they are burning the carbon in organic fuel is bonded with oxygen. At the same time some of the oxygen that is used to burn these fuels is bonded to hydrogen atoms from the fuel. One of the definitions of reduction reactions is the gaining of hydrogen. Therefore combustion reactions (like the one seen above) make great redox reaction examples.