Geographers use the regional unit to map features of particular interest, and data can be compared between regions to help understand trends, identify patterns, or assist in explaining a particular phenomenon. Regions are traditionally defined by internal characteristics that provide a sense of place.
I think the phrase you are looking for is "natural resources" - these include fresh water, food and fertile soil on which crops can easily be planted.
Answer:
Every river is part of a larger system—a watershed, which is the land drained by a river and its tributaries. Rivers are large natural streams of water flowing in channels and emptying into larger bodies of water.A tributary is a smaller stream or river that joins a larger or main river.
