Explanation:
Except in the crust, the interior of the Earth cannot be studied by drilling holes to take samples. Instead, scientists map the interior by watching how seismic waves from earthquakes are bent, reflected, sped up, or delayed by the various layers.
Basically the Earth is layered because of gravity. The earth formed in the molten state. The liquid iron which is very dense fell to the center. The rest of the earth is made up of silicate materials with SiO2 being the main component.
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Its a type of clay and is used for houses in other countries.
Increasing "Pressure or Temperature" is used to identify the layers of the atmosphere
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