I'm pretty sure it's the national road
He is best known for his work
The mandate of heaven is an honor that only good rulers are allowed to rule with other wise the others were just roked
Loss of factory jobs led to less in the middle class or you needed to work a white collar job to be middle class.
Industrial jobs moved overseas leaving those working in factories without jobs. Middle class jobs no longer included factory work but rather service jobs many requiring college degrees.
The lightbulb affected peoples lives most because people were able to stay up past sundown, and work longer hours.