Answer:
Cheap, fertile land
Discovery of Gold
Step-by-step explanation:
The settlers started to shift towards Western frontier of North America. This was the cause of the requirement of more land to grow and expand. The settlers have already expanded in the eastern areas therefore they opted to shift towards the western region. New land was required for farming and hunting that was gained by the process of expansion. Many of the Native American tribes were shifted and relocated. Free land for the use of farming and ranching was gained by this process. Some of the settlers also explored the land in search of gold during the gold rush.