Answer:
The Mexican army attacked them. The main cause of the war was the westward expansion of the United States. All through the 19th century Americans believed it was their right to expand westward. At the time they believed they could conquer the people already living on the land and take it for the United States.
Explanation:
Answer:
air pollution
That's what i think i dont know if its right.
Here are the answer's. "D""C""C""A"
Answer: Cities provided better opportunities.
Explanation: There were more jobs, leading to more opportunities to live a better life.