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)

Fusion of male and female gamete produces a zygote. Repeated division of the zygote is called cleavage forming a solid morula. After further division and rearrangement a fluid filled cavity surrounded by blastomeres - blastula is formed. The appearance of germ layers mark the gastrula.