Answer:
1. American Indians
2. Harsh Weather Conditions
3. Disagreements among political leader
4. Conflicts between settlers.
Explanation:
Given that the American frontier is a term used to describe the people or first settlers of the Americans in the United States during the westward expansion following the Louisiana purchase by the United States. These first settlers in the American expansion often referred to as the Old West or the Wild West, faces different obstacles, before finally overcoming them.
These obstacles we're the following:
1. American Indians
2. Harsh Weather Conditions
3. Disagreements among political leader
4. Conflicts between settlers.
