Which three physical regions make up Assam?

Assam is characterized by its diverse landscape, which is divided into three principal physical regions:

• The Brahmaputra River valley: Located in the north, this is the largest of the three regions. It is a fertile plain studded with low, isolated hills and ridges, surrounded by mountains on all sides except the west.1
• The Barak River valley: Situated in the south, this region forms an extensive lowland area that is vital for the state's agriculture.1
• The south-central hilly region: Located between Meghalaya to the west and Nagaland and Manipur to the east, this area features rugged topography, including the North Cachar Hills.1