Answer: the invention of cotton gin
Explanation:The cotton gin refers to a a machine that sets aside cotton fibers from their seeds. Therefore, the invention of the cotton gin transformed the cotton industry in the United States and demanded cheap labor force, which led to the rise of slavery in the South and to the American Civil War later.
I think it is the last one
The late 19th-century United States is probably best known for the vast expansion of its industrial plant and output. At the heart of these huge increases was the mass production of goods by machines. This process was first introduced and perfected by British textile manufacturers.
After the united states bought the Philippians archipelago from the Spanish in a sum of 20 million dollars, the US occupation of the Philippines has been significant for molding the nation towards its independence. One of its major proponents is American leaders like Roosevelt and Twain who granted the Philippine Islands sovereignty.
In 1839, a group of Africans took control of a Spanish ship called La Amistad that was bound for a port in Cuba where the Africans were to be sold as slaves. After seizing the ship, the Africans demanded to be taken back to their homeland, but were tricked by the ship's navigator who set a course that took them along the coast of North America. La Amistad was eventually captured by the United States Navy, and the Africans were held as pirates. Though they were almost taken to be sold in a U.S. slave market, a court case arose regarding whether they could actually be considered slaves. Abolitio
