The external foces of earth: the wind, water and people erode the relief of earth, theis changes occur slowly, over millions of years.
Erosion
Erosion is the constant wearing away of rocks and soil.Temperature,water,wind and people.
*sharp changes in temperature break rocks into fragments.
*rainwater,rivers and oceans constantly erode the ground
*people cut down forests.
The course of a river:
1: the river erodes materials in its upper course
2:waterfalls form in mountains or hilly areas
3:the river create deep gorges
4:the river deposits some materials in its middle course and creates meanders.
