Final answer:
The correct answer is a. Native American tribes, specifically the Cheyenne and Arapaho, who were massacred in the Sand Creek Massacre, an incident involving gross violence by a militia against a peaceful settlement under the leadership of Black Kettle, despite negotiations and visible signs of surrender.
Step-by-step explanation:
The massacre in the first war with the Cheyenne and Arapaho, referred to as the Sand Creek Massacre, involved the brutal killing of Native Americans, specifically the Cheyenne and Arapaho tribes. In Colorado, these tribes were attempting to resist land encroachment. Despite the Cheyenne leader Black Kettle's efforts to negotiate a peaceful settlement and the display of both the American flag and a white flag of surrender at their camp, they were attacked by a militia led by Colonel John Chivington. This brutal incident led to the deaths of close to one hundred people, most of whom were women and children.
The correct answer to the question about who was massacred in the first war with Cheyenne & Arapaho is a. Native American tribes.
It is true that during the period of European exploration and colonization, Native American tribes were frequently attacked and decimated by Europeans with superior weapons. Conflicts continued as American settlers pushed westward, with settlers and local militias often perpetrating the majority of the violence towards Native populations while expanding into the Great Plains.