The word biosphere is derived from the Greek word as bios as life and the sphere is the layer on the surface of the earth. Thus its the sphere where life on earth exists.
The biosphere is made up if the four-layer like the lithosphere, atmosphere, hydrosphere and thus is the sum of all the ecosystem. And a composition of all the abiotic and the biotic components of the real world.
Form single-celled to multi-celled organisms and thus is a natural ecosystem on the planet.
