Final answer:
The Interior Plains are described as the breadbasket of North America due to its rich fertile soils that make it perfect for agriculture. Additionally, their vast flat topography and rich subterranean oil and gas reserves are key characteristics. The flatness of the plains is due to their history as a seabed area.
Step-by-step explanation:
The Interior Plains are a spacious geographic region spanning through Central United States and Canada. Unique features of the Interior Plains include its vast flat topography, fertile soils and subterranean resources. Many areas of the Interior Plains have rich fertile soils that are ideal for agriculture, in fact, this region is often referred to as the breadbasket of North America. Besides, this region is known for its subterranean resources including oil and gas reserves, which contribute to a major part of its economy. The flat topography is due to its history as a seabed area during the prehistoric times.
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