All animals require oxygen. Most remove oxygen from the air through the lungs, although fish use their gills to remove dissolved oxygen from water. In animals, cells that do not receive oxygen die.
Oxygen is also required for combustion. Homes that burn fuel for heat require oxygen to support the flame. Every time the gasoline engine of a car starts, it uses oxygen that combines with the fuel to produce power.
Carbon dioxide is one of the waste gases that results from respiration in animals. It is required for plants to produce glucose for energy. Since carbon dioxide does not support combustion, fire extinguishers use the compressed gas to stop fires. Pressurized carbon dioxide, found in cans of soda, causes the bubbles in soft drinks.
Methane is a simple hydrocarbon consisting of one carbon atom and four hydrogen atoms. Methane is the primary ingredient of natural gas that many homes use for heat. Methane forms from the breakdown of plant and animal waste. Such breakdowns occur in swamps and manure heaps. Methane is a greenhouse gas that, along with carbon dioxide, contributes to climate change.Learn more about Chemistry