Q8-Explain the economic rules of Islam in the light of social justice? (2012)

What is being asked in the question? Is it the socio-economic system? How they are interlinked? What exactly is the economic rule that leads to social justice? Islam gives the right to personal profits and private ownership, and Nisab of Zakat is fixed. He raised some of us in degrees above others so that He may try us through what He has given us. Is it the collection of Jazya,fay,Kharaj,khums?

I repeat again, what is the economic "RULE" related to social justice?