How does interdependence in the bronze age lead to its downfall?

The interdependence that cause the bronze age to collapse are the natural disasters, droughts and tribal or pasoralist invasion.  The effect of the collapse of the bronze age are trades stopped between all of the different civilizations, populations died en masse, literacy almost disappeared completely and the empire was vanished. Civilization really start to make a comeback in the 900 BCE. The new period rise which is called as the iron age when the collapse of the bronze age happened. Iron is an ideal material for improving weapons and armor as well as plows. The invaders start doing iron weapons and they mastered the chariot and created new battlefield tactics that destroyed their civilized opponents.