Why did the united states become a leading industrial power in the nineteenth century?

During world war ll, the untied states was a member of the allies axis european theater pacific theater

Plz which of the following provisions of the compromise of 1850 was designed to appeal to slave states? a. congress passed a strict fugitive slave law. b. the slave trade was banned in washington dc. c. texas agreed to give away some of its land so that the territory would be available for future states. d. california was admitted to the union as a free state.

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