What was the main reason for the indian wars that took place in the region indicated on the map during the second half of the 19th century?

a. treaty violations by dissatisfied native american leaders
b. attacks by hostile native american tribes on u. s. military outposts
c. resistance to the new federal policy aimed at assimilating native americans
d. territorial pressures on native americans resulting from increased white settlement

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.

a stronger government