The reaction is an example of burning of methane. 

Respiration is a process that utilizes oxygen to breakdown glucose and release energy in the form of heat and ATP. It is a slow process that occurs inside living system only. However, burning is a fast process that occurs outside a living system.

Respiration occurs at low(body) temperature and burning occurs at high temperature. 

Oxidation of carbon and hydrogen present in carbon compounds and not food materials is an example of burning. 

Air surrounds earth as thick blanket called as atmosphere.

Air is mixture of colorless gases.

Energy is required to support life. Energy in our body is obtained from the food we eat. During digestion, large molecules of food are broken down into simpler substances such as glucose. Glucose combines with oxygen in the cells and provides energy. The special name of this combustion reaction is respiration. Since energy is released in the whole process, it is an exothermic process.
$\underset{Glucose}{C _6H _{12}O _6(aq)} + \underset{Oxygen}{6O _2(g)} \rightarrow \underset{Carbon dioxide}{6CO _2(g)} + \underset{Water}{6H _2O(l)} + Energy$

Breathing involves the exchange of gases in the lungs, a process which occurs by diffusion. The oxygen is then transported throughout the body. Carbon dioxide is the waste gas produced by respiration.

Cellular respiration resembles ordinary combustion or burning, in the break down of chemical bonds, use of oxygen, production of carbon dioxide and release of energy, but there are fundamental differences between the two processes.

In respiration oxygen breakdowns food substances mainly glucose and release energy in the form of heat. The carbon and oxygen that are oxidised are present in organic matter. Whereas in burning carbon and oxygen in inorganic matter is oxidized.

Respiration is defined as the movement of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction. The oxygen from air oxidises food substances mainly glucose in their body cells and release energy in the form of heat.

In respiration, oxygen breakdowns food substances mainly glucose and release energy in the form of heat. Also, it gives out carbon dioxide and water vapour.

Respiration is a slow process occurring inside the living systems only. Hence, it requires body temperature i.e., $37^0C$ to occur. Whereas burning occurs outside the living system. It requires a high temperature to initiate a chemical change.

A Pizza is the most heterogeneous mixture.
In a heterogeneous mixture the composition formed due to the mixing of components is not entirely uniform like in the case of grains mixed with dust etc.

When a balloon is filled with air then the air exerts force on the walls of the balloon. Due to this force the balloon material stretches and hence size of balloon increases. The material of the balloon is such that it can stretch a lot.