globular

There are 5 stages during the development of embryo, including the stage of 2-celled proembryo, multicellular proembryo, globular proembryo, pyriform proembryo, differential embryo and mature embryo.

胚胎发育经过二细胞原胚、多细胞原胚、球形原胚、梨形原胚、分化胚和成熟胚阶段。

We also describe the basic principle of white dwarf cosmochronology and its application in defining the age of the Galactic disk, globular clusters, open clusters and Galactic halo.

介绍星宇宙纪年学研究的基本原理及其在银盘、球状星团、疏散星团以及银晕年龄确定方面的应用现状。