Most history text books contribute the start of WWI to Nationalism. Briefly describe what is nationalism? Then discuss why might nationalism might cause a war like culture in many European countries during the early 20th century?

Nationalism is the view that nations are the basic units of human society, that they are the only legitimate basis for states and that each nation has the right to its own state. Nationalism is often accompanied by the view that the mixing of nations is evil, and in particular that some nations are in some way "superior" to other nations. This belief or policy has been the basis of nations' persecution of others for centuries and is still very prominent in many parts of the world today. Many wars have been waged because of this policy, and some are in full swing today. A clear example of this was nationalism in Europe, which led to the start of WWI.

b) brahmans   is nomadic society

i think it's a)sparta