The Ocean Life

We may look upon our physical world as made up of three elementary regions or spheres, each different from but intimately related to the other. First, there is the atmosphere, which is the benign mixture of gases which we breathe and which clothes the earth like a mantle. Secondly, there is the lithosphere – the zone of the rocks. It forms the crust of the earth, builds the continents, supports the ocean basins and makes up the dry land on which we live. Thirdly, there is the hydrosphere, the watery covering of the earth – the oceans and the seas…