As a result of the influence of gradient on the speed at which a river flows, it can be observed that ...... . Select one or more: a. on flatter ground, the river deposits more material than it erodes b. on steeper slopes, the river deposits more material than it erodes c. as a river flows onto its floodplain, its velocity slows and it deposits much of its load d. on flatter ground, the river erodes more material than it deposits e. on steeper slopes, the river erodes more material than it deposits f. at the headwaters of a river gradients are steep, water moves fast and work is done to erode the river bed