The development of the amazon basin has been stopped indian cultures made brazil a world power caused soil erosion

The development of the Amazon Basin has caused soil erosion

Soil erosion is defined as the wearing away of topsoil which is the top layer of soil and is the most fertile because it contains the most organic, nutrient-rich materials. One of the main reason for soil erosion is deforestation. Amazon being the largest rain forest in the world is in danger due to its development.  More than 20 percent of the Amazon rain forest is already gone, and much more is severely threatened as the destruction continues. It is estimated that the Amazon alone is vanishing at a rate of 20,000 square miles a year.

81 is a composite number.