The Russian Revolution was the result of which three main factors?

The Russian Revolution was a complex occurence at the time and was a consequence of three different and important streams of thoughts and influences of people which all wanted for Russia to develop in a certain way. One thing surely were the ideas of Marx and Engels which affected Lenin. Another thing was lack of food during World War I. And the last thing was that many soldiers were being lost at the fronts of the battlefield during WWI.