Solution:1) Corn laws: The British government restricted corn import because corn prices were lower than homegrown products. The laws allowing the government to limit the import of corn were known as "corn laws". This import restriction was put in place by the British government to support their native farmers.
2) Rinderpest: A contagious disease, Rinderpest had killed 90 per cent of the cattle in Africa in the 1890s. This disease kills livestock, and the African economy has been impacted because livelihoods depend on cattle.
3) Smallpox: Smallpox was a viral disease in North America in the 1600s.
4) Car Plant: Henry Ford introduced mass production to the US economy in the 1920s. He adopted the assembly line technique of a slaughterhouse; the assembly line method allowed for a faster and cheaper way of producing vehicles.