What was the Columbian Exchange?

O the opening of long-distance trade between the people of the Americas with the people of Europe
O the transporting of slaves from Africa to the Americas
O the introducing of new plants, animals, and diseases to and from the Americas and Europe
O the plundering of gold, silver, and other valuble things from the Americas to Europe

The Columbian Exchange refers to the introducing of new plants, animals, and diseases to and from the Americas and Europe.