In no less than 500 words, define and describe the Columbian Exchange. How did i

In no less than 500 words, define and describe the Columbian Exchange. How did it affect the relations among peoples of the Americas, Africa and Europe during this period? Use the following videos
Pre-Columbian America – Summary on a Map: 

New Empires Rise & Fall | Mankind: The Story of All of Us (S1, E8)
https://www.youtube.com/watch?v=mkBY_wZtBSE