Alliances is when two countries pair up,e.g. Belgium had an alliance with Britain and Belgium was being invaded Britain would come and fight the invading country even if they didn't want to do it to they would have to do it. There were many alliances in WW1 I think this is the main reason why the war started because if there were not any alliances no one would declare war on anyone.

You would have to sign a form to agree that you want

an alliance.