Chap.1 Natural resources: Air,Water,And Land
1. Air :
(1) The earth is surrounded by atmosphere which is made up of air.
(2) Air is a mixture of gases.
(3) Nitrogen, oxygen, carbon dioxide, six types of inert gases, nitrogen dioxide, sulphur dioxide, water vapour and dust particles are present in the air.
(4) The proportion of gases in spheres of the earth is as follows: •
A)80% of the total mass of gases in the air makes Troposphere.
B)19% of the total mass of gases in the air makes Stratosphere .
C) No gases found in Exosphere .
(5) The amount of gases is highest near the surface of the earth. As we go higher and higher from the surface, the proportion of gases goes on decreasing. Air is rarer at high altitudes.
2.water :
1)water, a substance composed of the chemical elements hydrogen and oxygen and existing in gaseous, liquid, and solid states.
2) It is one of the most plentiful and essential of compounds.
3) There is 71% of water on the earth surface.
3.Soil :
1)Soil is the loose surface material that covers most land.
2) It consists of inorganic particles and organic matter.
3) Soil provides the structural support to plants used in agriculture and is also their source of water and nutrients.
4) Soils vary greatly in their chemical and physical properties.
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