Which text in the passage suggests that it is a primary source

Who commanded fort union in the 1850's? what were their contributions to fort union?

What was one of the most important causes of the russian revolution of 1917? a. the german occupation of russia during world war ii b. the bolsheviks execution of czar nicholas ii and his family c. csar nicholas ii refusal to withdraw from world war 1 d. the policy of ethnic discrimination put in place by the duma

What were the four terms that american had to agree in order to live in mexico texas