Why do some historians argue that the common experience of the frontier was one of hardship and failure?

Which conditions did austria demand of serbia after the assassination of archduke ferdinand? check all that apply. 1. swearing allegiance to the triple alliance 2. accepting responsibility for the assassination 3. turning over control of its military operations 4. surrendering half of its most fertile lands 5. suppressing anti-austrian groups and publications

Which of these belongs to the united states after the spanish american war ?

What event caused germany’s economy to fail?