Question

why does mountain slopes have a thin layer of soil

Answer 1

since mountains have steep grounds, erosion and weathering occurs more and hence there is a thin layer of soil. it also depends on the quality of soil and vegetation which holds the soil.

Answer 2

the slopes of mountain,has thin layer of soil ..

1) it depend upon heavy rainfall
2) land slide
3) soil holding capacity

this all following points are responsible for the thin layer of soil in mountain slopes