Answer:
planform and cross-shore profile of the subaqueous beach, the subaerial beach and adjacent dune) will always tend to a state of dynamic equilibrium. If some parts are highly resistant to erosion (presence of hard outcrops or cliffs, for example), this can take a very long time. However, if the active coastal zone consists exclusively of loose sediments, a state of dynamic equilibrium can be reached in rather short periods, of the order of years or decades. The longer periods hold for beaches in the vicinity of coastal inlets. The beach state at equilibrium is not static, but fluctuates around the equilibrium state in response to fluctuations in hydrodynamic factors (tidal cycles, wave climate) and sediment supply.
Step-by-step explanation: