Most canyons are formed by flowing rivers through erosion over long periods of time.
Most river erosion occurs when the river is in flood.
Most canyons are formed by flooding over long periods of time.
what are most canyons formed by over long periods of time?

A. hurricanes
B. wind tunnels
C. dangerous
D. forces
E. kalenchoes
F. flooding
G. high populations
H. Sediment