The Native American way of life on the Great Plains centered around which two resources?

The introduction of standardized time zones (Eastern, Central, Mountain, and Pacific) in 1883 was primarily due to the efforts of: 

Who was the Hunkpapa Sioux leader who had a vision of soldiers falling from their horses before Custer’s Last Stand, and later surrendered in 1881 to prevent his people’s starvation?

The 1887 act that aimed to “Americanize” or assimilate Native Americans by breaking up reservations and giving land to individual Native American heads of household was the: 

Between 1870 and 1920, approximately how many Europeans arrived in the United States? 

 John D. Rockefeller gained total control over the American oil industry primarily by using:

The 1890 event where the Seventh Cavalry slaughtered 300 unarmed Native Americans, bringing the Indian wars to a bitter end, was the:

The immigration station in San Francisco Bay where Asians primarily gained admission

Bonanza farms were: 

Which of the following is NOT an isolating mechanism that protects resources, capabilities, or competencies from being imitated by competitors?