If there are every simply two countries fighting each other, then it's a typical war. However, when each of those two countries has a group of friendly nations who will help in case of war, then you have a world war.
In great Britain the alliances were to agree of support between countries
they all had alliances
In WW I the two major alliances were the Allies (or Allied Forces) and the Central Powers.
World War 2 was of two alliances. The Axis, and the Allies. Great Britain and U.S.A were on the Allies side.
The great depression of the 1930's influenced the power and alliances of the nations involved in WW2.
Cold War Alliances
Triple alliances and entente
During World War I: Europe's Great Powers Were Divided Into Two Loose Alliances The Triple Alliance: Germany, Austria-Hungary, and Italy - 1882 The Triple Entente: France, Great Britain, and Russia - 1907
Mania m militarism a alliances n nationalism i imperialism a assassination
Alliances greatly strengthened some countries, forcing others to increase their war budgets to prepare for contingencies. The Arms Race was significantly between Germany and the United Kingdom of Great Britain.
Yes, the alliances are what caused the war to spread around Europe. With out them, countries like Russia would not have fought in the war.
Alliances (by themselves) were not the cause of conflict in the Second World War. However prior to the First World War, Alliances played a contributing factor to the increase in tensions, the failure to resolve issues through diplomatic means, and the decisions of Austria-Hungary & Germany to launch offensive action against Serbia & France.