Which is an example of how the physical environment helped the Aztecs establish an empire?

1. The capital city of Tenochtitlan could be easily defended from attack.
2. The active volcanoes kept neighboring peoples from attacking the Aztecs.
3. The capital city of Tenochtitlan was located in the dense rain forest.
4. The Aztecs lived on a flat plain that was perfect for warfare.

1. The capital city of Tenochtitlan could be easily defended from attack.