Question

Identify the correct sequence.

• A. Zygote $\to$ Cleavage $\to$ Morula $\to$ Blastula $\to$ Gastrula
• B. Cleavage $\to$ Zygote $\to$ Morula $\to$ Blastula $\to$ Gastrula
• C. Zygote $\to$ Morula $\to$ Blastula $\to$ Cleavage $\to$ Gastrula
• D. Zygote $\to$ Blastula $\to$ Morula $\to$ Cleavage $\to$ Gastrula

Answer 1

The correct option is A Zygote $\to$ Cleavage $\to$ Morula $\to$ Blastula $\to$ Gastrula

The fusion of male and female gametes is called fertilisation which leads to the formation of zygote. After fertilisation, the zygote undergoes division to give rise to daughter cells by a process called cleavage. This results in a solid ball of 8-16 cells, called morula. It after further division develops into blastula. It contains a fluid-filled cavity called blastocoel. It ultimately leads to the stage called gastrula, a multilayered structure which is then followed by organogenesis.
Hence, the correct sequence is:-
Zygote $\to$ Cleavage $\to$ Morula $\to$ Blastula $\to$ Gastrula