The Badlands are a natural region located in western South Dakota. The name Badlands sounds like a desolate wasteland. Actually, this area consists of unique, pointy rock formations. However, the Badlands also include acres of beautiful grassland, resulting in the largest protected mixed-grass prairie in the United States. A shallow sea once covered the Badlands. Over millions of years, the land rose, and the sea disappeared. A warm, humid forest emerged, which later gave way to cooler grasslands. Rocks and soil contain clues to each era. Scientists continue to dig countless fossils and traces of ancient animals from the land. Questions about ancient life in South Dakota remain, but with each new find, the past becomes clearer.

What is the main idea of this passage?
(1 Point)
A. South Dakota contains many acres of grasslands.
B. Visually impressive, the Badlands offer clues to the region’s natural history.
C. Scientists can always find clues to a region’s past.
D. The ancient shallow sea of the Badlands provided a home for various animals and plants.