Complex sentence: The competences of the provinces vary amongst the autonomous communities they belong to, and in practical purposes, since the creation of the autonomous communities, their scope of action is minimal, with the exception of the historical territories of the Basque Country.
Split into simpler sentences: The competences of the provinces vary amongst the autonomous communities they belong to. Since the creation of the autonomous communities their scope of action is minimal, with the exception of the historical territories of the Basque Country.