Geological evidence suggests that many millions of years ago, the Amazon basin drained toward the west rather than the east. What caused this drainage reversal?

a rise in the global sea level

a lowering in the global sea level

the rise of the Andes Mountains

global climate change

the rise of the Andes Mountains

Explanation:

Geological studies in the area suggest that the Amazon River originated during the Miocene about 11.3-11.8 million years ago, first as a transcontinental river at a time when present-day South America and Africa were united in western Gondwana. It is believed that it flowed from east to west, and not the other way around.

The elevation of the land and the formation of the Andes towards the end of the Cretaceous, as a result of the clash between the Nazca plate and the South American plate, caused the body of water to become an inland sea that gradually acquired swampy characteristics. About 11 million years ago, water began to flow eastward to the lowlands due to the blockage of the flow caused by the Andes, and flowed into the ocean. Its current form dates back 2.4 million years ago.