The area near the surface of the earth can be divided into four interconnected spheres: lithosphere, hydrosphere, biosphere, and atmosphere.
1) The lithosphere, sometimes called the geosphere, refers to all of the rocks of the earth. It includes the planet's mantle and crust, the two outermost layers.
2) The hydrosphere is composed of all of the water on or near the planet's surface. This includes oceans, rivers, and lakes, as well as underground aquifers and the moisture in the atmosphere.
3) The biosphere is composed of all living organisms: plants, animals and one-celled organisms alike.
4) The atmosphere is the body of gasses that surrounds our planet, held in place by earth's gravity. Most of our atmosphere is located close to the earth's surface where it is most dense.