Why does the density of life change in different parts of the biosphere?

The biosphere in biology is called the shell of the Earth, in which living organisms can exist.

The biosphere covers the troposphere (part of the atmosphere), part of the lithosphere and the entire hydrosphere.

The population density of living organisms in different parts of the biosphere is different. Living organisms can be found both in underground waters and in oil layers, below the soil layer – in caves and in deep cracks. However, most of all living organisms are on the surface of the earth: in forests, along water bodies. Because there is more food and sunshine.