Answer:
1)Circumstances that helped the civilizations and diverse cultures of the Americas to develop in ways both common and unique are the early civilizations of the Americas created such vast empires with an advanced form of thinking and living. These civilizations lacked some of the essential tools that the Asian civilizations depended on to form there amazing empires.
2) The Conquistadors were professional soldiers, having served in the Spanish Army. ... The Spanish had arrived at the right time to conquer. They came at a sacred time on the Aztec calendar when Aztec Emperor Montezuma wasn't allowed to re-train or replenish the army. The Spanish played psychological warfare, unknowingly.
3)A large number of the enslaved were destined to remain in Africa - many were transported across the Sahara to the north - which heightened the impact of the slave trade on the continent. ... Besides its demographic toll, the slave trade, and the Africans' resistance to it, led to profound social and political changes.