To have backup and protection
I would think it would be D
They can't collect surplus food, as they are nomadic and constantly moving. They hunt animals, and use there skins for clothes. If this doesn't help, I'm sorry. I'm an idiot. :)
The Plateau society differed from Northwest coast society in various aspects.
- The coastal society was very strict with its social classes while as there were no social classes in Plateau society.
- The chief of Coast society was hereditary while as chief of Plataea society was chosen on the basis of merit and ability.
Besides these differences there were some similarities between the two. Both were worshipers of nature and believed in spirits. The important economic activity of both these people were food gathering.