What evidence does the article provide in regards to the purposeful development of Incan farming methods? What farming methods did the Incas use to adapt to their local environment?

The article states that the Incas developed knowledge of farming in the Andes region over the course of 11,000 years. This information shows that they refined their farming practices over time. The use of gravel, terraces, and canals allowed the Incas to adapt farming to the difficult terrain.