I believe the answer is: b. loss of money for candidates
The seventeenth amendment Regulate the appointment process of senate and prevent the candidates to use government's budget to fund their campaign.
In order to win, the candidates have to obtain the majority through popular votes by the people of the state and search for their campaign fund by using their own money or outside contributor.
The Neolithic Revolution, also called the Agrarian Revolution, was the change from a nomadic, hunter-gatherer lifestyle to a settled, agrarian one with farming. Farming is more stable and secure and it gives people more time to engage in other activities, such as improving their tools and developing cultures: the neolithic Revolution contributed to the technological development in the river valley civilisations by giving people time to improve on their technology.
The answer is D, having to fight a two-front war.
The Schlieffen plan was the German strategy to quickly take out France so that they could focus all their troops on Russia.
