Match the following. match the items in the left column to the items in the right column. 1. accretion the gaseous layer of a planet usually retained by its gravity 2. atmosphere process of steady growth of an object by a steady accumulation of material 3. biosphere the water system of the earth; includes solid, gas, and liquid water 4. cryosphere a process creating different layered compositions of a planet 5. differentiation the rigid, crustal layer of earth 6. hydrosphere the system of earth by which living organisms exist 7. lithosphere the frozen water or ice system of a planet