This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'Ameloblasts are formed  after: \nSelect and explain. \nA. Dentin is laid down., B. Odontoblasts are formed., C. Predentin is laid down., D. None of the Above.', 'role': 'user'}, {'content': "Answer: B \nExplanation: AMELOGENESIS\nAmeloblasts begin enamel deposition after a few micrometers of dentin have been deposited at the dentinoenamel junction, At the bell stage, cells of the inner enamel epithelium differentiate. They elongate and are ready to become active secretory ameloblasts. The ameloblasts then exhibit changes as they differentiate and pass through five functional stages:\n(1) morphogenesis,\n(2) organization and differentiation,\n(3) secretion,\n(4) maturation, and\n(5) protection\nGolgi's apparatus appears centrally in the ameloblasts, and the amount of rough endoplasmic reticulum (RER) increases in the apical area.\nThe row of ameloblasts maintains orientation by cell-to-cell attachments (desmosomes) at both the proximal and distal ends of the cell. This maintains the cells in a row as they move peripherally from the dentinoenamel junction depositing enamel matrix.", 'role': 'assistant'}]