COMPOSITION OF ATMOSPHERE

Air is mainly composed of Nitrogen (78%) and Oxygen (21%).  The table below gives the composition of air by volume.
 
 
Nitrogen N2 78%
Oxygen O2 21%
Argon Ar 0.9%
Carbon Dioxide CO2 0.03%

Traces of other elements found are Neon (Ne), Helium (He), Methane (CH4), Nitrous Oxide (N2O), Hydrogen (H2), water vapor, carbon monoxide, ammonia, and solid particles such as dust and pollen.

The relative amounts of the major components, Nitrogen, Oxygen, and Carbon Dioxide remain constant because  they are involved in the life processes of plants and animals.  These gases are taken and replenished.  Nitrogen is taken by the plants and released during organic decay.  Animals inhale oxygen and exhale carbon dioxide , while plants convert carbon dioxide into oxygen.

Plants produce oxygen by photosynthesis, the process by which carbon dioxide and water are converted into sugars (needed for plant life) and oxygen using energy from the Sun.  For more information, click below.

 Photosynthesis

The key to photosynthesis is the ability of chlorophyll, the green pigment in plants, to convert sunlight into chemical energy..  Billions of tons of carbon dioxide are removed from the atmosphere every year and replaced by billions of tons of oxygen.  Over half of the photosynthesis occurs in oceans which contain many forms of green plants.  Click below for more information about chlorophyll:

 Chlorophyll



 
 
 
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