why do you think the period from 1877 to world war 1 can be called the beginning of the "long american century"?

Jacksonian democracy promoted new methods of political campaigning. one such technique was mudslinging. what was its effect on the presidential candidates?

The northwest ordinance guaranteed three rights for the settlers of the northwest territory. what were they?

The information box says that the han added 4,000 miles of wall.refer to the mileage scale.how can this be true?