It absorbs CO2, It plays an important role in the heat energy balance.
1. helps transformation from gas to liquid help form latent heat (this an important source for Atmospheric energy),
2. It is also a green house that absorbs the earth outgoing radiant energy,
They provide a good balance between the size and shape of land areas.
Up here topically a majority of our mountains and craters are results of volcanoes and earthquakes that are caused by moving tectonic plates. on the ocean floor the features are caused by the same things. there are under water mountain ranges and craters.