What impact did german u-boats have on allied shipping during ww1 ?

Which action by the us war department angered chief red cloud to the point that he refused to sign the treaty of fort laramie ? a) the killing of buffalo by the united states troops b) the appointment of troops to the powder river basin c) the burning of parts of the powder river basin d) the murder of chief red cloud’s wife

Did the spanish settlers and missions have a positive effect on world history? why, what did they do that was positive? why was the treaty of paris (1763) good for the world/world history? did the plymouth colony have a positive effect on world history? why, what did they do that was positive?

In keeping their culture unchanged what do canadians fear the most?