Answer:
they wanted to expand the territory under their control because of overpopulation.
Explanation:
<span>Some people in the late 1800s believed that to improve the situation of Native Americans, they could assimilate into American culture as citizens and landowners. This would break up the reservations into individual allotments where families could then support themselves. </span>
A pyramid is usually used as a tomb, but I think they can be used as an arena as well.
You can search this up on the internet if you are not completely sure.
hope this helps :)
They were not protected by the government