One of the major motivations for altering the environment in Mexico City was __________.

A major reason people altered the environment around Mexico City was to create more usable farmland. For example, the Aztecs developed chinampas—fertile agricultural plots built in the lake’s shallow waters—to grow crops. Thus, “creating arable land” is the best answer; reducing population growth and dependence on agriculture were not the main motivations.

AI-written and checked against the verified answer.