True, Geology has the greatest effect on soil building.
<u>Explanation</u>:
The process of weathering is studied under the science of geology and there are many factors that play a role in soil building. It is affected by climate, slope and many other factors.
The parent material is most important part of soil formation which is studied by geologist.The various rocks, minerals, their formation and their eventual denudation into soil and in later stage,change into rocks again comes under physical geology.
Thus, even though the factors like slope, climate and various external factors play role in soil building, the greatest effect is of geology.
