This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Primordial germ cell is derived from \nSelect and explain. \nA. Ectoderm, B. Mesoderm, C. Endoderm, D. Mesodermal sinus', 'role': 'user'}, {'content': "Answer: C \nExplanation: Primordial germ cell is derived from epiblast, earlier they were believed to arise from endoderm of yolk sac They became evident at the distal end of primitive streak by the 2nd week of intrauterine life, these cells migratory and reach the endodermal wall of yolk sac, they reach the gonad by the 5th week Gray's 39e/p-210-220", 'role': 'assistant'}]