Write any four characteristics of cleavage.

Explanation

(i) It is rapid mitotic division of zygote to form multicullular structure blastula. (ii) The resultant cells are called as blastomeres. (iii) The blastomeres become smaller and smaller during cleavage as there is no growth during division so it is also known as fractionating division. (iv) The nuclear cytoplasmic ratio goes on increasing as the cleavage progresses, because of DNA replication but no cytoplasmic synthesis.