Final answer:
The fertile farmland between the Mississippi River and the Appalachian Mountains is the Midwest and Great Plains, also known as America's breadbasket, with fertile agricultural land and prominent grain farms and corn belts.
Step-by-step explanation:
The fertile farmland situated between the Mississippi River and the Appalachian Mountains encompasses the Midwest and Great Plains regions in the United States. Recognized as America's breadbasket, this area boasts some of the world's most fertile agricultural land. The climate becomes progressively more arid as one moves westward, and the nature of agriculture adapts accordingly to varying precipitation levels.
In the eastern part of the region, characterized by more abundant water resources often supplemented by irrigation, grain farms and corn belts are prominent. This agricultural diversity, from grain production to corn cultivation, contributes significantly to the nation's food production and underscores the importance of the Midwest and Great Plains in sustaining the agricultural foundation of the United States.