The first box
Explanation:
The velocity structure of a stream flowing over low gradients with easily eroded banks will erode straight channels into meandering channels.
Erosion - outer meander bends where the velocity is high.
Sediment deposition - the inner meander bends where the velocity is low forms exposed bars called point bars.
When meandering streams erode continuously on the outer meander bends and depositing sediment along the inner meander bends, it leads to migration across their flood plain backward and onward.
