Chaurs in Bihar plain are

The correct answer is: A. oxbow lakes.

Oxbow lakes are formed when a river meanders and then cuts off a meander, leaving behind a crescent-shaped lake. Chaurs in Bihar plain are oxbow lakes.

Oxbow lakes are common in floodplains, where rivers are constantly changing course. When a river meanders, it creates a series of loops. Over time, the river may cut through the neck of one of these loops, creating an oxbow lake.

Oxbow lakes are often home to a variety of wildlife, including fish, birds, and reptiles. They can also be important for flood control and water storage.

Here is a brief explanation of each option:

• A. Oxbow lakes are formed when a river meanders and then cuts off a meander, leaving behind a crescent-shaped lake.
• B. Flooded plains are areas of land that are regularly flooded by rivers.
• C. Highlands are areas of land that are higher than the surrounding land.
• D. Levees are artificial embankments that are built to protect land from flooding.