Why did the Tsarist autocracy collapse in 1917

Why did the Tsarist autocracy collapse in 1917?

Answer: The Tsar first dismissed the initial two Dumas and then packed the parliament with the conservatives. During the First World War, the Tsar took decision without consulting the Duma. Large scale casualties of Russian soldiers in the war further alienated the people from the Tsar. Burning of crops and buildings by the retreating Russian armies created huge shortage of food in Russia. All of these led to the collapse of the Tsarist autocracy in 1917.