How does raising crops to be sold differ from raising crops to eat?

What led to violence in kansas in 1854? a.) northerners and southerners disagreed over the results of the slavery vote. b.) people in kansas wrote the fugitive slave law. c.) people voted for kansas to be a free state. d.) nebraska was split into kansas and nebraska

What is the name for the main idea behind the settling of western lands by americans in the early-1800s?

Why do many scientists suppose the land bridge theory of migration?