Why Is It That The World Has The Longest Rivers?

The world's longest rivers are usually found in high altitude or mountainous areas. The water must rise against gravity in order to get to lower elevations, where it can be utilized for water or for agriculture. Furthermore, rivers that flow through fertile terrains tend stay elevated longer than those that don't because they are able to transport more sediment and nutrients. https://www.freejobalert.com/longest-rivers-in-the-world/994260/