Q. The Son River valley forms the boundary between which two plateaus?
Answer: Kaimur and Chotanagpur
Notes: The Son River valley separates the Kaimur Plateau (west) and Chotanagpur Plateau (east). Kaimur is part of the Vindhyan range, while Chotanagpur is a rich mineral region. This natural boundary influences local geography and drainage patterns in eastern India.