Answer:
I don't know but need these points so I'ma comment
I believe the first one is 'physical geography' :-)
<span>Erosion by rivers is a main valley-forming
process; other processes, such as movement of the earth's crust and
glaciers, also have an important part in some cases. The rate at which a
river deepens its valley depends on several factors.</span>
Answer:
from which. Hope you understand me
