After the franco-prussian war, why did germany form alliances and start to build up its military?
germany wanted to invade italy to unite germans living within italy.
germany wanted to annex belgium to unite germans living in belgium.
germany feared that great britain would form an alliance with france.
germany feared that france wanted to recapture alsace and lorraine.

Germany feared that France wanted to recapture Alsace and Lorraine.

Explanation:

The Franco-Prussian War was fought between the Second French Empire and the Kingdom of Prussia over the extension of the German territory. The war came to an end with the sign of the Treaty of Frankfurt in 1871 which gave Germany the French territories of Alsace and Lorraine.

France wanted its territories back so, because of the fear of another Franco-Prussian War is that Germany started to build up its military.

It was a key conflict for what it would come later, World War I.

I hope this answer helps you.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).