Most grass embryos have a flap-like structure known as the epiblast . 大多数禾本科胚有一片瓣状结构通常称为外胚叶。
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The neurofibromas are multiple benign neoplasms of the peripheral nervous system, arising from mesodermally-derived schwann cells . 神经纤维瘤是外围神经系统的多发良性肿瘤，由中胚叶的雪氏细胞发生。
