This is clipart converted and broken apart that has been released into the public domain because the document says so, and its from NASA, a USA government agency. The publication is called "The Brain in Space:" http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/The.Brain.in.Space.html
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anatomy、astronomy、brain、converted、diagram、government、medical、nasa、science、space、usa
解剖學、天文學、腦、轉換、圖、政府、醫、上、科學、空間、使用
資料來源：openclipart ( https://openclipart.org/ )