Answer: B
Explanation:
The water was provided, and carefully controlled, by a combination of natural springs and artificial constructions such as aqueducts, dams, canals, reservoirs, and gates. One of the most impressive of these was the 16 km d built by Nezahualcoyotl on the edge of Tenochtitlan to block the salty water of Lake Texcoco and create a lagoon supplied by a fresh water spring.
The Calhoun doctrine shows that Calhoun wanted states to have the right to nullify national laws
Answer: Cities provided better opportunities.
Explanation: There were more jobs, leading to more opportunities to live a better life.