The surface of the earth is a complex interface, because three main components of the environment meet, overlap and interact on it.
Lithosphere: The solid portion of the earth is Lithosphere. In Greek Litho means stone or rock. It means the sphere made of rocks is termed as Lithosphere.
Atmosphere: The gaseous envelope surrounding the earth is Atmosphere. In Greek ‘atmo’ means air. The sphere made of air is atmosphere.
Hydrosphere: The area containing water is called Hydrosphere. Word, Hydrosphere has been derived from the Greek word ‘Hydro’ which means water. Hydrosphere contains water in all its forms.
Biosphere has been derived from the Greek word ‘Bio’. It includes all parts of earth where all types of organisms live. It is the narrow zone of contact of land, water and air where all forms of life are found.
All the four realms are not separate entities, they are considerably intermingled.