What is the longest river in South America?

The Amazon River is recognized as the longest river in South America, spanning approximately 4,345 miles (7,062 kilometers) from its source in the Andes Mountains to its mouth at the Atlantic Ocean. The Amazon River system is also one of the most complex and biodiverse rivers in the world, draining parts of several countries, including Brazil, Peru, and Colombia.

While other options might include significant rivers, they are either located in different continents or are shorter in length compared to the Amazon. The Mississippi River, for example, is the longest river in North America and does not play a role in South American geography. Similarly, the Nile River is the longest river in Africa, making it unrelated to the question. The Orinoco River is a major river in Venezuela, but it is not as long as the Amazon, measuring about 1,300 miles (2,100 kilometers). Hence, the Amazon River stands out as the correct answer due to its remarkable length and geographical significance.