The major split in Islam is that between the majority Sunnis and the minority Shiites. The split goes back to events in the 7th century. After Mohammed’s death in 632, leadership of the Islamic community passed to Abu Bakr as-Siddiq, one of Mohammed’s closest companions.
Answer:
they lasted for more than 200 years
Any practices should best be based on a research - this is the correct answer. (a. child development and research) Research is the best source of actual knowledge, rather than people's best guesses (people's best guesses might lead government regulations, but it would be better if they also followed research results.).
