How did the changes brought about by reservation treaties like the treaty of fort laramie affect american indians in the mid- to late 1800s? a. standards of living for the average american indian increased with access to modern medicine and sanitation technology. b. desperate american indian groups began launching violent attacks against white americans in greater numbers. c. american indian leaders lost their political authority as their tribes shifted loyalty to white reservation officials. d. american indians saw a revival of their traditional cultures due to their separation from white american society.