Complex sentence: The High Karst Unit (or High Karst Zone) is a tectonic unit in Slovenia, Croatia, Italy, Bosnia and Herzegovina, Kosovo, Serbia, Montenegro and Albania.
Split into simpler sentences: The High Karst Unit (or High Karst Zone) is a tectonic unit in the Balkans region of Southeastern Europe. It is found in Slovenia, Croatia, Italy, Bosnia and Herzegovina, Kosovo, Serbia, Montenegro and Albania.