Final answer:
The freshwater supply from the Tiber River to Rome was transported by underground channels called aqueducts.
Step-by-step explanation:
The freshwater supply from the Tiber River to the city of Rome was transported by underground channels. These channels, known as aqueducts, were built by the ancient Romans to transport water from distant sources to the city. The aqueducts were constructed using a combination of arches and tunnels, allowing the water to flow downhill by gravity.
Learn more about transportation of freshwater in ancient Rome