Examine the reasons that led to the great Zimbabwe

If you mean the fall its is a decline in land productivity would led to famine and a combination of overgrazing and drought caused the soil on the Zimbabwe Plateau to become exhausted.

If you mean the rise the wealth in the great soil, pastures where livestock could live, trade between shoba and the indian zone and the amount of mining to get rich resources like gold, iron, tin and copper all led to the rise.