Explain the similiarities and differences between combustion and food digestion?

Digestion is not an example of combustion. Digestion is an endothermic process where energy is utilized to break down the complex food molecules into simple forms. In a combustion reaction carbon dioxide,water,energy and some by products are released.

Explanation:

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.