Why does erosion take place in the earth's crust?

Question

(Ha, yah, I should know this, but I'm tired, it's the weekend and I can't find it in my book....=( Thanks to all who answer in advance!) If this helps, the question on my paper was, 'In which layer does erosion take place?' (The crust.) And then the next part, (The part I need help with.) is 'Why?'

Answer 1

And the answer is something like, "because that's the layer that is exposed to the weather."

The crust is the surface layer. Wind-blown sand, rivers, glaciers, etc. are all on or above the surface. So it is only the surface layer that erodes.

Answer 2

How Does Erosion Take Place