How is federalism different from popular sovereignty

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

Which of the following describes an effect of world war ll on the united states economy a. automobile companies produced a record number of cars b. many factories had to expand to produce military equipment c. the airplane industry suffered as the allies began using airplanes in combat d.cities with shipyards declined because so many ships had been sent overseas.

Which act intended to regulate and trade?