Final answer:
Santo Domingo is the city in the Dominican Republic that has both an international airport and an international seaport, as well as being the site of an FTZ (Free Trade Zone).
Step-by-step explanation:
The city that has both an international airport and an international seaport, as well as being the site of an FTZ (Free Trade Zone), is Santo Domingo. Santo Domingo is the capital city of the Dominican Republic and is located on the southern coast of the country. It is home to Las Americas International Airport and the Port of Santo Domingo, making it an important transportation hub.