Why does earth have a great physical variations. Mentioned any three causes.

Explanation:

The processes used by these actions are known as Weathering and Erosion.

Rainfall (water from the cloud) falls carrying out two major actions, firstly, it dissolves chemicals in the atmosphere and this solution causes chemical reactions on the various surfaces it falls on thereby weakening those surfaces through this action and secondly, by its impact on it wears off the surface. This second action becomes more vivid when you study the impact of a drop of water on a sandy surface. The impact dislodges the soils particles from others.

When there is significant amount of rainfall it leads to runoff (water running on the surface) and this runoff has enough force to move loose soil and rick particles to be deposited at a new location. The movement of these particles causes wear and tear on the surface on which they are moved and over time a new landscape evolves.

Water in the form of ice also causes significant landform changes especially in the temperate regions. This occurs through a process called ice or frost wedging. This essentially means water lodging in cracks and crags of rock get frozen and since frozen water expands it forces the crack to become wider and often times dislodging part of the rock surface.

i'm sure the answer you are looking for would be

a. an ice age

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