How did the use of the horse change the lifestyle of Native Americans on the Great Plains? please do not use links

Why was it decided in potsdam that certain industries in germany would be disabled? a. to deplete resources that might prevent germany from coming to power again b. so that a portion of the eastern region of poland would be fused together with the soviet union c. to allow the allies to focus their war efforts in fighting the last part of the war against japan d. to provide economic aid for iran's government since large war demands were made on them