There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
Net worth: $829 million. Telecommunications mogul Strive Masiyiwa is widely regarded as the richest man in Zimbabwe and is one of the richest men in Africa with a net worth of more than US$800 million.
No.2 Aliko Dangote. Aliko Dangote is worth $11.2 billion after making money from interests in sugar, flour milling, salt processing, textiles, real estate, oil, gas and cement. He is the richest person in Nigeria, richest black in the worth and the 51st richest person in the world.