In order to carve out valleys, glaciers have to be strong enough to drag rocks and boulders down the mountainside, but what else has to happen for glaciers to create glacial valleys?
a. to create valleys, glaciers have to move at a rapid rate of several miles a day.
b. to create valleys, glaciers have to completely melt and freeze over thousands of years. this total melting causes solid rocks to crack and decompose.
c. to create valleys, glaciers have to be constantly retreating.
d. glaciers have to be soft enough to move, and it is this movement that drags the rocks and boulders responsible for carving earth’s surface.
e. to create valleys, glaciers have to be constantly advancing.