How did humans move across continents?

How many citizens of mexico does it take to equal the ecological footprint of the average citizen of the united states? it takes nearly three mexican citizens to equal the ecological footprint of the average u.s. citizen. it takes about 12 mexican citizens to equal the ecological footprint of the average u.s. citizen. it takes just over eight mexican citizens to equal the ecological footprint of the average u.s. citizen. two citizens of mexico equal the ecological footprint of one average citizen of the united states. they are essentially equal?

Before the civil war, the south’s economy was based on enslaved labor. large cities. immigrant workers. factories.

How did the phoenicians add to the goods available in their marketplaces?