2. What are the religious differences?
Shiite Islam is far more hierarchical than Sunni Islam. Shiites venerate the ancestors of Muhammad in a way that Sunnis do not. Almost all religious Shiites follow an Ayatollah, a senior Islamic scholar, as an “object of emulation.” They follow their Ayatollah’s edicts on how to square the facts of modern life with Islamic doctrine. Sunni Islam is far “flatter” in its organization, with less of a formal process needed to become a preacher and far less centralization of clerical power. In this respect, the differences between Shiite and Sunni Islam superficially approach the differences between the Catholic Church and most Protestant denominations.
In daily practice, there are subtle differences in the way a Shiite or a Sunni may pray or perform ritual ablutions.