Q: The world recently marked the centennial of the start of World War I. What was the cause of World War I and which countries participated in it?

—Frank Burnette, Decatur

A: There were many reasons leading to the start of World War I, which was ignited by the assassination of Archduke Franz Ferdinand of Austria-Hungary in Sarajevo, Bosnia, on June 28, 1914.

Many European countries were undergoing economic and political changes 100 years ago and a series of treaties had formed the Triple Entente (Britain, France and Russia) and the Central Powers (Germany, Austria-Hungary, the Ottoman Empire and Bulgaria). Those countries, and others, also were challenging each other globally in a race to collect colonies and increase their empires.

After Ferdinand was assassinated, Austria-Hungary, backed by Germany, took action against Serbia, which was allied with Russia. Germany invaded Belgium and France in August 1914. About 40 countries (including territories and colonies) declared war at some point and took part in some way, but some their contributions were insignificant and came late in the war.

Q: What happened to two TV shows “Game of Stones” and “Siberian Cut?” It seems they were dropped in mid-series. Will they return?

—Don Baerwalde, Kennesaw

A: Discovery Channel hasn't decided if "Game of Stones" and "Siberian Cut" will return for their second seasons, a spokeswoman told Q&A on the News in an email. "Game of Stones" follows gem hunter Don Kogen, who looks for "rare stones from the most dangerous and lawless places on earth." In "Siberian Cut," American Sean Vann has a logging contract in Siberia.

Andy Johnston wrote this column. Do you have a question about the news? We’ll try to get the answer. Call 404-222-2002 or email q&a@ajc.com (include name, phone and city).