This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Development period- week 1,2,3,4, Subject name: Anatomy
[{'content': 'Which process establishes the three definitive germ layers? \nSelect and explain. \nA. Neurulation, B. Gastrulation, C. Craniocaudal folding, D. Lateral folding', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Gastrulation - three primary germ layers from epiblast during week 3 of development i.e dorsal ectoderm, middle mesoderm, ventral endoderm. Neurulation is the process by which neuroectoderm forms the neural plate, which eventually folds to form the neural tube.', 'role': 'assistant'}]