Here's why:

* Geological Formation: The Great Plains were formed over millions of years through a combination of geological processes including uplift, erosion, and deposition.

* Climate: The Great Plains have a unique climate, characterized by semi-arid conditions and vast grasslands, which are naturally occurring.

* Biodiversity: The Great Plains are home to a diverse array of plant and animal life, which evolved and adapted to the natural environment.

While human activities have impacted the Great Plains, the fundamental landscape and its defining features are a result of natural processes.