I am not sure if I an right but I think the answer is D.
The only option that is not generally a reason why historians study societal change would be "<span>d. to estimate how long it would take to build a road system," since this requires a separate type of research. </span>
Answer:
The revolutions of 1848 ignited nationalist sentiment throughout the Italian peninsula. The Franco-Austrian War of 1859 was the agent that began the physical process of Italian unification. The Austrians were defeated by the French and Piedmont at Magenta and Solferino, and thus relinquished Lombardy.
Explanation:
The 1929 stock market crash is conventionally said to have occurred on Thursday the 24th and Tuesday the 29th of October. These two dates have been dubbed “Black Thursday” and “Black Tuesday,” respectively. On September 3, 1929, the Dow Jones Industrial Average reached a record high of 381.2. At the end of the market day on Thursday, October 24, the market was at 299.5 — a 21 percent decline from the high.
Answer:
The United States has been the most powerful nation in the world ever since sometime in 1943 becuase The United States, had the most powerful military the world had ever seen. At the end of World War II, the United States Navy had the largest and most well trained naval forces.
Explanation: Hope this helps. :)