Answer:
1-A: A cataract is another term for waterfall
2-E: Ex. European countries colonized North and South America centuries ago
3-F: Escarpment is a word for a steep cliff or slope
4-B: A topographic map shows the geographic features of an area
5-D: A tributary is a smaller stream that always flows into a bigger one
6-C: Veldt is another word for a plateau