Which were major causes of conflict between native americans and white settlers in the 1800s?
choose all answers that are correct.

a. the common native american practice of ignoring treaties that they had signed

b. the slaughter of buffalo herds on which native americans depended for food

c. the effort by native americans to secede from the u. s. and form their own government

d. the issue of who owned and controlled the land, and for which purposes it should be used