Explanation:
waterfalls are temporary features of rivers because stream erosion is greatest at waterfalls and rapids. The water that falls at the base of the waterfall erodes rock there, leaving the rock at the tops of the waterfalls to overhang. Overall, undermining causes waterfalls to recede farther upstream.
Geography is the study of the physical features of the earth and its atmosphere, and of human activity as it affects and is affected by these, including the distribution of populations and resources, land use, and industry
I believe the answer is C due to the fact that delta is built from rocks, mud, soil and moraines is built from rocks, sand, gravel and soil (I tried)
