Mountain slopes have faster erosion because it is easier for fast moving bodies of water to carry down eroded material downhill, rather than across flat land.
Well, I know 4 is A and 5 is D.
Clear-cutting is the most common method of timber removal. Clear-cutting removes all the trees in a given area, often by using large machinery. From an economic standpoint, the benefit of this approach is that humans can harvest maximum timber with minimal energy and cost.
