Answer:
Roman engineers used inverted siphons to move water across a valley if they judged it impractical to build a raised aqueduct. The Roman legions were largely responsible for building the aqueducts. Maintenance was often done by slaves. The Romans were among the first civilizations to harness the power of water.
Explanation:
The workers who worked at factories faced the qorst wirking and living condition in mid-nineteenth-centry America.
Monroe doctrine
Monroe doctrine warns European countries to not colonize or puppet monarch
