1. According to Bono, agricultural subsidies in the U.S. harm farmers in Africa. Why?

What is exactly the welfare effect that is responsible for that outcome according to Figure 1?

Figure 1 U.S. Subsidies Reduce African Exports P S P* P* * - - - - I- PD - - ---/. - - - - - - D QD QD Q's Q Q U.S. farm subsidies reduce the world price of this crop from P* to P**. Exports from this African country fall from Qs-QD to Q's-Ob