Question

The correct sequence in the process of development of human embryo is

• A. fertilization—zygote—cleavage—morula—blastula— gastrula
• B. fertilization—cleavage—morula—zygote—blastula—gastrula
• C. fertilization—zygote—blastula—morula—cleavage—gastrula
• D. cleavage—zygote—fertilization—morula—blastula—gastrula

Answer 1

Answer: (A)

fertilization—zygote—cleavage—morula—blastula— gastrula

Answer 2

Zygote - morula- blastula - gastrula - embryo

Zygote is the first cell that is formed after the fusion of sperm cells and the egg cell.

After multiple rounds of division through cleavage, it forms a solid ball called a morula. After that there is a formation of fluid filled hollow balls of cells called blastula. Gastrula have invagination and cell migration that results in the formation of three germ layers. The process of organogenesis forms embryos.