From January 2011, the price of orange juice increased by about 80%.

1. How would I provide two separate explanations for this price increase using shifts in supply or demand? Can you please explain how?
2. What is an example of one piece of information would allow me to decide which of the two is a better explanation?

This second example is - The Chocolate Candy Bars Market-

1. In the accompanying diagram (which represents the market for chocolate candy bars), the initial equilibrium is at the intersection of S1 and D1. Where would I circle the new equilibrium if there is an increase in cocoa prices? Can you explain please?
2. In the same diagram, the initial equilibrium is at the intersection of S1 and D1. Where would you suggest be circled for the new equilibrium if there is rapid economic growth? Please can you explain?

Price Quantity D2 S2 S1 D1 D3 S3