What were the two most important items exchanged that came from the Old World to the New World?

As we have learned in Unit 3, one of the global effects of the Age of Exploration, and specifically of the discovery of the New World, was an incredible exchange between the Old World and the New World. This is known as the Columbian Exchange. It resulted in the movement of massive amounts of plants, animals, diseases, and peoples along with cultures and technologies that ultimately spread across the world. For this discussion, you will study the Columbian Exchange and consider its impact, posting your conclusions and perspectives in the discussion forum.

To begin, watch (or rewatch) the Crash Course video on the Columbian Exchange, which is included below. This will provide you with an overview of the exchange and its influence. After watching the video, do your own research on the Columbian Exchange and its impact in preparation for posting in the forums. When you are ready to post, please respond to all four of the following questions about the Columbian Exchange:

1. What were the two most important items exchanged that came from the Old World to the New World? Why were they so important?
2. What were the two most important items exchanged that came from the New World to the Old World? Why were they so important?
3. What was the most significant problem caused or liability introduced in the Old World and in the New World by the Columbian Exchange? Explain.
4. In your opinion, was the overall impact of the Columbian Exchange positive or negative? In other words, would the earth have been better off without this exchange? As you discuss your perspective, explain both the major positive and negative effects that guide your opinion.