Acts rigidly and is brittle. A semi-plastic layer below the lithosphere. Hydrological Cycle is driven by the sun and gravity, wears down Earth's surface through streams, glaciers and waves erosion. Water has enabled life to form on the planet. Ice is found at both poles of Earth as an ocean covering sea ice in the arctic, and a 4000 m thick glacier in Antarctica.
Life is responsible for oxygen in the atmosphere.
It is also found in the atmosphere and deepest oceans. Life is also found several kilometers deep in Earth's crust. The earth can be divided into two major areas.