The Columbian Exchange - VIDEO
The link address is: https://www.khanacademy.org/humanities/ap-us-history/period-1/apush-old-and-new-worlds-collide/v/the-columbian-exchange
The link address is: https://www.khanacademy.org/humanities/ap-us-history/period-1/apush-old-and-new-worlds-collide/v/the-columbian-exchange