Final answer:
The Otranto Strait is the narrow body of water that divides the heel of Italy's boot from Albania, lying in the southern Adriatic Sea.
Step-by-step explanation:
The strait that separates the heel of the boot of Italy from Albania is known as the Otranto Strait. This narrow passage of water lies in the southern Adriatic Sea, marking the boundary between the Italian Peninsula and the Balkan region of southeastern Europe.
Unlike the Strait of Gibraltar which separates Spain from Morocco and connects the Mediterranean Sea with the Atlantic Ocean, the Otranto Strait specifically acts as a geographic divider between Italy's southeastern coast and Albania's northwestern border.