The diagram above is a soil profile. it represents different soil layers and the parent material from which the soil forms. the topsoil layer is at or near the surface, and the parent material can be several meters below the surface.

porosity is one of many characteristics that varies in soil. porosity is a measure of how much empty space a soil sample has between its particles—the more empty space there is, the greater the porosity.

given that particles deeper underground tend to pack more closely together due to gravity, place the soil layers in order of increasing porosity.

a. c horizon → subsoil → topsoil

b. topsoil → c horizon → subsoil

c. topsoil → subsoil → c horizon