Rewrite the following sentences, choosing the right word from those given in brackets :
(Humus / Regolith) is produced by the decayed organic material, including **** leaves, stems roots, living bacteria, fungi, worms and other organisms.
(Weathering / Denudation) refers to the gradual disintegration and decomposition of rocks which lie exposed to the elements of weather.
(Young / Mature) soils are those which are undisturbed by erosion or deposition.
(Hydration / Carbonation) occurs when the water itself combines chemically with some element or mineral.
(Oxidation / Solution) is the chemical process in which some of the minerals are dissolved by the water.
