The Maginot Line was the primary defense for the French during World War 2.
Answer:A
the Incan civilization was known for the impressive waterworks in their city centers. Some of these included canals, fountains, drainage systems, and expansive irrigation.
One example of their advancement in this area is the Incan citadel called Machu Picchu which is said to be "the pinnacle of the architectural and engineering works of the Inca civilization" when talking about its water supply system.
The main factor was the utilization of raised field agriculture. They would build these fields that had been artificially raised to a certain height along a flowing water source (mostly rivers but occasionally streams as well in some cases). When tropical weather patterns would cause said water sources to flood, instead of washing away the crops, it would act as irrigation for the raised fields. Securing a steady food source allowed the Mayans to support a large civilization in the tropical regions they called home.
Farming made civilization possible in Americas because we were able to make crops to make food which kept us alive.