Atmosphere – thin layer of air above earth surface – it is held by gravity
Biosphere – it is a narrow zone of earth where land, air and water interact to support life
Ecosystem – is the system formed by interaction of living organisms with each other and with physical and chemical factors of the environment they live in
Crust – main constituents – Silica and Alumina (SiAl)
Mantle – SiMa (Silica and Magnesium)
Core – Nickel and Iron (NiFe)
Igneous rocks – when molten lava solidifies – also called as primary rocks
When it solidifies outside earth’s surface – it is called Extrusive igneous rocks – since it cools down rapidly they have fine grain structure – ex- basalt – deccan plateau is made of basalt
When it solidifies under the earth’s surface – it is called intrusive rocks – since it cools slowly – have coarse grain structure – Ex – Granite
Sedimentary rocks – sediments deposited by water, air. Ex – sandstones
Igneous and sedimentary rocks can change into metamorphic rocks under high pressure and temperature – ex – clay into slate and limestone into marble
