Question

Which of the following stages is the first one out of sequence?

Options

• Cleavage

• Blastula

• Morula

• Gastrula

Answer 1

Cleavage

Explanation:

Cleavage is the first stage after fertilization where the zygote undergoes repeated mitotic divisions to form a solid ball of cells called morula. After morula, blastula forms, followed by the gastrula. So, cleavage is the first stage, and therefore none of the other stages come before it.