Question

As the initial cleavage divisions proceed in a frog embryo, what happens next?

Answer 1

Cleavage divisions lead to formation of blastula.

Explanation:

()

After fertilisation of egg by sperm, cleavage divisions begin.

Cleavage involves mitosis of cells in early embryo in rapid succession without intermittent growth phases. This helps in establishing normal nuclear cytoplasmic ratio (as the zygote is associated with more cytoplasmic mass compared to the nuclear volume of cell).

At the end of cleavage divisions a hollow ball of cells appear, which is called blastula . The cavity inside blastula is called blastocoel.

Blastula later undergoes gastrulation , another embryonic event: to establish three germ layers of frog's body.