Native Americans.
Africa
Native Americans.
Native Americans.
I will use them to enslave humanity, allowing me to take over the world!
Africans were enslaving each other long before Europeans got into the act, if that's what you're trying to ask. A significant number of slaves transported from Africa to the New World were purchased from other native Africans.
The Europeans explored the New World with ships.
Contact with the Europeans changed life in the new world by...?
Which voyages gave Europeans new knowledge of the world?
Contact with the Europeans changed life in the new world by...?
Europeans wanted to explore the world so that they could gain wealth
The Europeans
Disease came with the Europeans. The old world brought diseases to the new world and they had no natural immunity to them.