Which of the following features could be found in the upper course of rivers?

One of the features that could be found in the upper course of rivers is a waterfall. The upper course of a river is the section closest to its source, where the river is typically narrow and has a steep gradient. Waterfalls often form in the upper course of a river when a band of hard rock overlies softer rock that is more easily eroded by the flowing water. The softer rock is gradually eroded away, leaving a steep drop or waterfall over the hard rock layer. Ox-bow lakes, on the other hand, are formed in the lower course of a river when the river meanders or bends and erodes the outer bank, causing the river to cut a new channel and leave a curved lake behind. Deltas are formed at the mouth of a river, where the river meets the sea or a lake and deposits sediment, creating a fan-shaped landform. Levees are raised banks that form along the sides of a river as a result of sediment deposition during flooding events. Overall, waterfalls are a common feature found in the upper course of rivers, while ox-bow lakes, deltas, and levees are typically found in the lower course of rivers.