What was the main way the Incas modified their environment to grow more food

They developed resilient breeds of crops such as potatoes, quinoa and corn. They built cisterns and irrigation canals that snaked and angled down and around the mountains. And they cut terraces into the hillsides, progressively steeper, from the valleys up the slope.

seeing as no choices were provided, i'll do my best to answer it from knowledge.

job specialization promotes work ethic to the person doing the job. he/she may be strong in the arms and able to lift things, specializing him/her in a job where you lift and carry.

the answer i chose to believe is 'harmony'