Answer:
Cotton
Step-by-step explanation:
At that time, cotton was considered as cash crops. Is the type of agricultural crop that generate high amount of income with very little investment /efforts. Many southern plantations sold the cottons to Other manufacturers in Europe since they need it as materials for textiles, outdoor equipment's, and beds.
This made a lot of plantation owners in the South had a need to obtain lands in order to open up new factories. A lot of lands near them at that time owned by Native Americans. So, the government forcefully removed the natives from the ancestral land and move them to reservation.