Why was there a revolution in Iran in 1979?

NOW UPDATED WITH A GENERIC MARK SCHEME AT THE REQUEST OF SUBSCRIBERS!
This question will be investigated through a Hexagons exercise. Students will be presented with a large amount of hexagons, with each one providing one key piece of information. Students will have to arrange these into meaningful groups that highlight the connections between the factors. I have written a detailed article about the hexagons approach here. I have also programmed an Online Hexagons Generator.

I have already uploaded a complete Practice Sourcework Paper in the style of IGCSE on the theme “Why was there a revolution in Iran in 1979?”