I have a few questions about World War I that I can't seem to find information about in any textbooks or online:

Question

Was Russia forced to act in defense of Serbia to protect access to the warm water of the Black Sea?

Did France extend support to Russia in an effort to recover lands lost to Germany in the Franco-Prussian War?

Answer 1

I don't think "forced" is the appropriate word. However, Russia and Serbia had an agreement that Russia would help defend Serbia.

http://www.firstworldwar.com/origins/causes.htm

Here's the details of the agreement between Russia and France.

http://wwi.lib.byu.edu/index.php/The_Franco-Russian_Alliance_Military_Convention