The correct sequence of embryonic development is:

• A) Blastula-morula-zygote-gastrula-embryo
• B) Zygote-blastula-morula-gastrula-embryo
• C) Zygote-morula-blastula-gastrula-embryo
• D) Gastrula-morula-zygote-blastula-embryo

The correct sequence of embryonic development is option B: Zygote-blastula-morula-gastrula-embryo. This sequence outlines the stages that occur after fertilization, starting with the zygote, which then develops into a blastula, followed by the morula, and then the gastrula, ultimately forming the embryo.

Stages of Embryonic Development

• Zygote: The fertilized egg, the initial stage of development.
• Blastula: A hollow sphere of cells that forms after several divisions.
• Morula: A solid ball of cells that results from the division of the blastula.
• Gastrula: A stage where the cells begin to differentiate into various layers.
• Embryo: The developing organism that emerges from the gastrula stage.

Understanding these stages is crucial for studying developmental biology and the processes that lead to the formation of complex organisms.