Consider the topic of population changes resulting from the Columbian Exchange. Which claim is most effective?

The population and habits of people in the Americas changed because of the Columbian Exchange.
The worst impact of the Columbian Exchange was that it decreased the indigenous populations in the Americas.
The Columbian Exchange was important for many reasons, including population shifts in both the Americas and Europe.
One interesting impact of the Columbian Exchange was the way it changed indigenous populations of the Americas.