The U.S. in 1846 was not justified in going to war with Mexico, they didn't have justification to respond with violence.
The reason why the Mongols withdrew form Asia was because of horrible weather conditions and diseases. If I had to pick, I would pick A.) Diseases because A is more severe then the weather conditions.
an expansion of settlement and growth in the western towns
Explanation:
By the early 1700s, the fur trade was firmly established in the Great Lakes region. The French empire was based on the fur trade in this region and required Native American alliances to sustain it. Native people and the French traded, lived together, and often married each other and built families together.
It is spread by infected mosquitoes.