Final answer:
The three phases of embryonic development in chronological order are cleavage, gastrulation, and organogenesis.
Step-by-step explanation:
The three phases of embryonic development in chronological order are cleavage, gastrulation, and organogenesis.
Cleavage is the rapid division of the zygote into smaller cells, forming a solid ball called a blastula. Gastrulation is the process in which the blastula undergoes reorganization and forms three germ layers: endoderm, mesoderm, and ectoderm. Finally, organogenesis is the development of organs from the germ layers.