earth it always changing.one way is changes is by erosion.some is caused by the weather.for example,the wind causes erosion.in a desert,the wind blows the sand around.rain also caues erosion.it washes away earth and even changes the shape of some rock.anotherkind of erosion is causad by rivers.when a river goes through a mountain,ut cuts into the mountain.after a long time,the mountain is lower and the land us flatter