The correct answer to this open question is the following.
European settlers and Americans transformed the Great Plains from natural grassland to fields of corn.
The Great Plains are a vast portion of prairies with just a few trees. When worked correctly, it can be transformed into great fields for agriculture. That is what European settlers did in the American territory known as the Great Plains. From being natural grassland to productive agriculture fields. We are referring to United States territories such as Nebraska, Kansas, South Dakota, North Dakota, Oklahoma, Montana, Colorado, New Mexico, Wyoming, and Texas. In Canada: south Alberta, Manitoba, and Saskatchewan.
