Horses were passed from the old to new worlds. Horses were used as a transportation service. The impacted the new world (Native Americans) by revolutionizing Native American life, permitting tribes to hunt the buffalo far more effectively.
This disease mostly affected the Americans. This disease came from Europeans through trade and interaction.
Missionaries either forced or told people to convert to Christianity. If those people did not covert when told they were killed because missionaries thought that being another religion was disrespectful to GOD. Sometimes they were killed by the disease.
Slaves were used for picking food and sugar cane from the feilds and they were used to find gold for their masters. If they did not bring back enough gold their masters would kill or torcher them.
Americans used their riches to pay for food and trade of food and their needs.