* Abrasion: This is the wearing away of landforms by the grinding action of rock particles carried by wind, water, or ice.

* Corrosion: This is the chemical decomposition of rocks by acids in water or air.

* Hydraulic action: This is the erosion of landforms by the force of water.

* Attrition: This is the wearing away of landforms by the bumping of rock particles against each other.