Answer:
Two: mechanical and chemical
Shay's rebellion is the last thing that occured
The Spanish also enslaved Africans.
It grew through military conquest to cover a huge region that roughly encompasses today's Iran, Iraq, Armenia, Afghanistan, Turkey, Bulgaria, many parts of Greece, Egypt, Syria, much of what is now Pakistan, Jordan, Israel, the West Bank, the Gaza Strip, Lebanon, Caucasia, Central Asia, Libya, and northern parts of ...