As settlers moved west in the 1800s, which region was the most difficult for them to cross? Explain.

Area 3

Explanation:

Because it consisted of mountains and rugged terrain.

Explanation:

Once they embarked, settlers faced numerous challenges: oxen dying of thirst, overloaded wagons, and dysentery, among others. Trails were poorly marked and hard to follow, and travelers often lost their way. Guidebooks attempted to advise travelers, but they were often unreliable.

answer; biological;