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': 'Microcrystalline polished layer that forms on a metal surface is called \nSelect and explain. \nA. Beilby layer, B. Rogue layer, C. Bilbe layer, D. Knoop layer', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Beilby layer\nSir George Thomas Beilby proposed that when a metal is polished, a film forms on the surface due to plastic flow of the metal. He inferred that when a solid is caused to flow, as in polishing due to heat generated, the crystalline surface is broken down to form a harder and denser surface layer.The Beilby layer explains the hardening of metals under cold working. This worked layer thus can be defined as an amorphous, disorganized molecular surface layer of a highly polished metal, which is a result of melting and surface flow during machining of the molecular layers such as using a series of\xa0abrasives of decreasing coarseness during the polishing processes.\nMaterials Used in Dentistry-\xa0 S. Mahalaxmi page 578', 'role': 'assistant'}]