Third planet from the Sun and the only known planet to harbor
life. About 29.2% of Earth's surface is land with remaining
70.8% is covered with water. Earth's distance from the Sun,
physical properties and geological history have allowed life to
evolve and thrive.
Source : Wikipedia
Earth's interior, like that of the other terrestrial planets, is
divided into layers by their chemical or physical (rheological)
properties. The outer layer is a chemically distinct silicate
solid crust, which is underlain by a highly viscous solid
mantle.
Source : Wikipedia
The total surface area of Earth is about 510 million km2. The
continental crust consists of lower density material such as the
igneous rocks granite and andesite. Less common is basalt, a
denser volcanic rock that is the primary constituent of the
ocean floors.
Source : Wikipedia