Many plains indians who were forced onto reservations had trouble adapting because they were
a. not used to living within borders.
b. used to hunting for their food.
c. not used to living in communities.
d. used to working in factories,

The correct answer is A) not used to living within borders.

Many Plains Indians who were forced onto reservations had trouble adapting because they were not used to living within borders.

With the passaging of the Indian Removal Act of 1830, US President Andrew Jackson was allowed to remove Native American Indians that lived in the south of the US to move to the west of the Mississippi to the Indian territory, what today is Oklahoma. This decision did not like the Native tribes such as the Cherokee because they were used to live with no boundaries. They were free in their former lands and now the US federal government forced them to live in Reservations.