第3个回答 2017-02-23
The rearrangement of the blastula into a three-dimensional organismwith inner, middle, and outer layers occurs during gastrulation. The resulting gastrula consists of an outerectoderm, an inner endoderm, and a mesoderm layer positioned between them.
在原肠胚形成过程中，囊胚重新排列，形成包括内层，中层，外层的三围组织。最终原肠胚由一个外肠胚，内肠胚，和一个中肠胚构成。