Why were the native americans of the great plains in competition with the settlers for land?

For these reasons:

- The native Americans had to fight to their native land, where they had developed customs and traditions. Otherwise the settlers of the land were competing to find them a place to cultivate and settle.

- They native Americans had to compete if they didn't want to die easy or just let their "captives" destroy them. We all know in the game of competition rules are broken and morality is less important.

- The natives may have been friendly with the settlers at first and then problems came causing them to have to count the cost of being friendly and now let their natural survival instincts kick in.

On the side of the settlers they may have been vicious as one side of history paints them. Playing friendly to the landowners until they had enough time to put their schemes for territory into action.

Please vote my answer brainliest. thanks!

Ithink i think the answer is c or b