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| Composition of Environment:Atmosphere, Lithosphere,Hydrosphere,Biosphere |
Atmosphere : It is the gaseous envelope that surrounds the earth. Its major components are Nitrogen ( 78% ), Oxygen ( 20.96% ), Argon ( 0.93% ), Carbon-dioxide ( 0.032% ), and other inert gases. The earth's environment can be divided in four major zones or layers
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| Composition of Atmosphere Troposphere Stratosphere Mesosphere Thermosphere |
- Troposphere : The zone immediately above the surface of the earth is called the Troposphere. Its height extends upto 20km above the equator and 8 km above the poles. 75% of the Atmosphere's mass is found in the Troposphere.
- Stratosphere : The layer above the Troposphere is called the stratosphere. It extends upto an attitude of 50km. The temperature in this region increases slowly due to absorption of ultraviolet radiations. This layer is an important zone of the Atmosphere at it contains the Ozone layer. The Ozone layer protects the Earth from the Harmful ultraviolet rays that come from the sun which have a potential to cause destruction to living beings/life and property.
- Mesosphere : It is a zone above the Stratosphere with thickness of about 40km and extends upto 85km from the surface of the earth.
- Thermosphere : This zone lies above the Mesosphere where temperature increases with height. Most of the constituents in this zone are in an ionized state.
Lithosphere : The earth's crust consists of rocks and soils made up of different chemical elements and minerals.
Biosphere : The biosphere is the living component of the environment. It forms a thin crust of living beings spread over the surface of the earth and constitutes all its states of living sysytem the existences of well being of living organism ( micro and macro ) depend on a sytem of complex interaction within and inbetween the components of environment ( lithosphere hydrosphere and biosphere ).

