Why is the diatomic nitrogen molecule diamagnetic rather than paramagnetic?
Despite nitrogen regularly having 3 unpaired electrons in its p orbital, the use of a molecular orbital diagram shows that there are actually no unpaired electrons present. This explanation is a result of the application of the Molecular Orbital theory.
What was a direct result of the Mongol conquests on the Muslim world?
The sack of Baghdad by Hulagu Khan saw the final destruction of the once mighty Abbasid Caliphate - the void left by this would eventually lead to the rise of the Ottomans and Safavid Empires. These empires were uniquely different from previous Muslim powers, in that they no longer adhered to the idea of Arab superiority nor did they use Arabic as the language of administration.
How did World War I start?
The formation of numerous and convoluted alliances, widespread militarism amongst the Great Power, and the imperialistic tendencies of the European powers which led to increased tensions and wishes for power were all some of the indirect factors which eventually led to World War I. However, the direct cause is much simpler: the assassination of Archduke Franz Ferdinand in Sarajevo, by Gavrilo Princip, sparked a series of events which resulted in the Great Powers being drawn in, one by one, into the 'Great War'.