Question

Cleavage is a succession of rapid cell divisions that follows fertilization. During cleavage

• A. number of cells increase and embryo enlarge
• B. number of cells increase and size of cells decrease
• C. number of cells decrease and embryo does not enlarge
• D. number of cells neither increase nor decrease but forms blastomeres.

Answer 1

Answer: (B)

Cleavage is a series of rapid mitotic divisions of the zygote which convert the single celled zygote into a multicellular structure called blastula or blastocyst. This process is not characterised by cell growth, hence, number of cells increases but their size decreases and hence no enlargement of the embryo is observed.