Conflicts between the sioux indians of the plains and the us army spanned from a. the 1820s to the 1850s. b. the 1860s to the 1890s. c. the 1870s to the 1900s. d. the 1880s to the 1910s.

The correct answer is B. Conflicts between the Sioux Indians of the Plains and the US Army spanned from the 1860s to the 1890s.

Explanation:

The Sioux Wars were a series of armed conflicts between the United States of America and the Sioux tribes in the second half of the XIX century. The beginning of these wars was the Grattan Massacre of 1854, when a group of warriors killed a Mormon's cow, and in retaliation Colonel William Harney took them condemned to Fort Laramie, after killing many of them.

The Sioux Wars finally ended in 1890, with the Wounded Knee Massacre.

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explanation:

. political or economical policy that isolates a country from participating in international relationships. it has been suggested that the united states participates in isolationism because of its lack of involvement in particular wars or alliances.