Answer: A river basin can be defined as an area of land drained by the river and its following tributaries. It covers the land area where the rainwater is collected as a whole and is stored and drained in a proper drainage manner.
The largest river basin in the world is The Amazon Basin. The Amazon Basin is situated in the Northern part of South America. The area which is covered by the Amazon River and its following tributaries rounds up to seven million square kilometres of land area which the Amazon River drains. The Amazon River basin has a wide area and a huge number and biological diversity. It has a dense population of many insect species.