They are neither. They form however as a result of weathering and erosion which could be considered "destructive" forces.
Cliffs are typically considered as a result of destructive forces, such as erosion from water or wind wearing away the land over time. However, cliffs can also be formed through constructive processes, like when tectonic activity pushes land upwards to create steep rock walls.
destructive
constructive and destructive
is deposition constructive or destructive
ocean waves are both, that's why you have different types of coasts - eg - cliffs, beaches from diffent types of erosion
no destructive they erode the land. In places that are flat like Florida there are no high waves but in California where there are cliffs the waves are higher.
it is both constructive and destructive
hurricanes can be both constructive or destructive.
Destructive. Destructive means destroying and constructive means to make something. An earthquake is both destructive and constructive.
There are four forces in the universe: electromagnetism, gravity, and two you've almost certainly never heard of, neither of which is "cliffs". The question doesn't make a great deal of sense.
both constructive and destructive forces
is a cave a constructive force or a destructive forcce