Question

Which of the following is the correct sequence in embryo development?

• A. Cleavage, gastrulation, blastulation
• B. Blastulation, cleavage, gastrulation
• C. Cleavage, blastulation, gastrulation
• D. Gastrulation, blastulation, cleavage

Answer 1

The correct option is C Cleavage, blastulation, gastrulation

The zygote is the first cell that forms after fertilization. This zygote undergoes rapid mitotic divisions known as the cleavage.

The cleavage results in the formation of an 8-16 cell structure known as the morula.

Blastulation is the next step that leads to the formation of blastula from the morula. The blastula has two type of cells, outer trophoblast and the inner cell mass and a cavity known as blastocoel.

Morphogenetic movements take place in this blastula and form a gastrula and this is known as the gastrulation. The cavity of gastrula is known as the archenteron.

So, the correct option is 'Cleavage, blastulation, gastrulation'