The professor talks about a couple of advanced technologies Roman cities used to expand. The first technology is an advancing building material called concrete. Concrete can harden under water. Romans use this concrete to build strong bridges across wide rivers. This bridge can also transport heavy materials. So Roman cities can grow on both sides of the river. The other technology is called aqueduct. Aqueduct is a water channel that can move water from water source to the city. The flow is very steady. And tremendous water can be transported to great distances. So the Roman cities can expand without locating near rivers.
A sample Answer to this speaking in text:
The professor talks about a couple of advanced technologies Roman cities used to expand. The first technology is an advancing building material called concrete. Concrete can harden under water. Romans use this concrete to build strong bridges across wide rivers. This bridge can also transport heavy materials. So Roman cities can grow on both sides of the river. The other technology is called aqueduct. Aqueduct is a water channel that can move water from water source to the city. The flow is very steady. And tremendous water can be transported to great distances. So the Roman cities can expand without locating near rivers.