Which was the greatest challenge for both american settlers and american indians in the west in the mid-1800s?

The greatest challenge for both American settlers and American Indians in the West in the mid-1800s was a)the exposure to harsh weather. Many settlers and pioneers had to go against harsh weather conditions, such as gales, arid desert conditions and long winters. Since the western part of the United States has different geography, there were many different instances throughout the seasons that the pioneers and settlers had to face.