What are the three main components that make up the earth?
Why just 3? Earth scientist now recognize a number of Earth system "spheres"
Earth scientists now think of the Earth as a complex system with a number of parts, called "spheres". The geosphere is the crust, mantel and core; the hydrosphere is all the water on the planet, cryosphere is the frozen ice on the world, atmosphere are the gases, and the biosphere is life. Some scientists have suggested adding a "anthrosphere" to this list which is all the impacts humans are having on the planet.