what is the biosphere of the earth?
The Earth's Biosphere. The biosphere is defined as the sphere or area around the planet Earth where life exists. This zone of life is vast. Most lifeforms live on or near the surface of Earth. However, some live deep within the hydrosphere (oceans, lakes and streams), while others thrive in the depths of the lithosphere (solid portion of Earth). For this reason, mapping the exact borders of the biosphere is quite challenging.