Answer:
Because there was an argument on which was better, Capitalist and Communist. This problem lead into the Cold War.
Explanation:
Actually two answers are correct: on an island and in a marshland.
Tenochtitlan is today's Mexico City and Mexico City was located on a lake called Texcoco that was dried so that people could live there. Before the arrival of the Spaniards, the Nahua lived on an island on this lake, surrounded by water and marshland
I think it is Religion I'm not sure