During cleavage, the zygote divides repeatedly to convert the large cytoplasmic mass into a large number of small blastomeres. It involves cell division without growth in size because cells continue to be retained within the zona pellucida. However, cell size decreases during cleavage.
Related Theory
Holoblastic cleavage is a complete cleavage meaning it completely penetrates the egg. Meroblastic cleavage is incomplete or partial cleavage meaning it does not penetrate the egg completely.