What is he columbian exchange

Refers to the transfer of new animals plants, (and even diseases) from the Old World (Europe) to the New World (Americas)

I believe that's right.

The Columbian Exchange refers to a period of cultural and biological exchanges between the New and Old Worlds. Exchanges of plants, animals, diseases and technology transformed European and Native American ways of life. Beginning after Columbus' discovery in 1492 the exchange lasted throughout the years of expansion and discovery. The Columbian Exchange impacted the social and cultural makeup of both sides of the Atlantic. Advancements in agricultural production, evolution of warfare, increased mortality rates and education are a few examples of the effect of the Columbian Exchange on both Europeans and Native Americans.