In the 1860s, tensions in colorado between american indians and white settlers led to a massacre at little bighorn. sand creek. wounded knee. pike’s peak.

Sand Creek

Explanation:

From the early 1860s until the late 1870s, the frontier raged with Indian  wars. In 1864, Colorado’s governor persuaded most of the warring Indians in  his territory to gather at Fort Lyon, on Sand Creek, where they were promised  protection.But like many other cases of settlers brutality against indigenous people that was only a disguise. Colonel John M. Chivington's used a white flag to fool a peaceful Indian camp and his 675-man force to massacre a number around of 200 Indians.

b, the anti immigrant fervor

the group i'm selecting: greeks.

a first group of greek immigrants came to the us in the 1850s. the second group came to america starting in the 1890s due to economic opportunities they didn't have back in their home caused by the hardships of ottoman rule. greek immigration was 90% male, many of them expected to work and return to greece after earning enough capital, but ultimately had to remain in the us after the greek genocide.