What characteristic is typical of the lower course of a river?

In the lower course of a river, the landscape typically features a flat floodplain. This area is formed as the river approaches its mouth and loses velocity, leading to the deposition of sediment and the widening of the river valley. The floodplain area is characterized by low-lying land that is prone to flooding during high water events, creating fertile land often used for agriculture.

The formation of a floodplain is significant because it allows for the natural overflow of a river during periods of heavy rainfall or snowmelt, which can enhance soil fertility through nutrient deposition. The smooth topography of the floodplain contrasts with the steeper and more rugged terrain often found in the river's upper and middle courses. This allows for a slower, meandering flow of water, which is typical of the lower course of a river.

In comparison, features like interlocking spurs, deep gorges, or narrow valleys are more representative of a river's upper course, where erosion dominates and landscapes are typically steeper and more rugged. The flat floodplain, therefore, is a defining characteristic of the smooth, gentle nature of the river's lower course.