Question

During embryogenesis archenteron formation is preceded by
A. Blastulation
B. Neurulation
C. Gastrulation
D. Implantation

Answer 1

Fertilization is described as the fusion of haploid male and female gametes to form a diploid zygote. The zygote undergoes cleavage and forms 2,4,8, and 16-celled stages. The 16 celled stage is known as the morula, which divides and converts into a blastocyst. It implants into the uterus and begins gastrulation. During gastrulation, archenteron formation takes place.

Complete answer:
During gastrulation, the formation of the primary gut is known as the archenteron of the digestive tube. The archenteron develops from the endoderm and mesoderm of an animal. During embryogenesis, gastrulation is described as the formation of germ layers. It begins from the inner cell mass that contains stem cells. These stem cells have the potency to form all the tissues and the organs.
There are three germ layers:
- Ectoderm
- Endoderm
- Mesoderm

The ectoderm is the outer layer that forms the entire nervous system, skin, the special senses, and endocrine glands. The endoderm is the inner layer that forms the digestive and respiratory system. The mesoderm is the middle layer present between the ectoderm and the endoderm. It forms the skeletal, urinary, circulatory, and reproductive systems.

Therefore, it is clear that archenteron or digestive tube formation occurs in gastrulation. The embryo development occurs in three stages and these are germinal stage, gastrulation, and neurulation.The archenteron formation is preceded by the process of neurulation.

Hence, the correct answer is option (B).

Note: Archenteron and blastocoel are two different cavities. Archenteron is the primitive gut that forms during gastrulation. On the contrary, blastocoel is the cavity present within the blastula and forms during blastulation.