How did tensions in europe lead to war

They lead to war in multiple ways and multiple times. Usually when there were tensions in Europe, the leaders of two or more nations that were soon to be at war, had arguments/accusations and at first perhaps tried solving the problem diplomatically. When that failed, they resorted to violence and tried causing damage to the other nation. 

Several different things make up a culture like, how the people worship, their form of government, geography, and trade. religion is one of the most important things to a culture, it defines peoples life. their different beliefs form into festivities and events that merge with their culture. people that practice hinduism see cows as gods, so no doubt they would celebrate cows, and these celebrations would definitely merge with their culture. those that are buddhist live life trying to reach a certain level of peace, so no doubt would they change things in their life in order to correspond with their religion.