Explanation:
C
Clevage a series of mitotic divisions where by the enormous volume of egg cytoplasm is divided into numerous smaller nucleated cells. These cleavage stage cells are called- blastomeres.
Several types of cleavage symmetry seen in nature radial (echinoderms, amphibians), spiral (mollusks, annelids), bilateral (ascidians, tunicates), rotational (mammals).
In deuterostomes cleavage pattern is radial \& indeterminate.
Radial- The cells divide such that seen cell in the top four cell plane is directly over one other cell in the bottom plane.
Indeterminate- Early embryonic cells retain capacity to develop into a complete embryo if isolated from other cells. Cleavage produces blastomeres which are qualitatively equipotential or totipotent. When they are isolated, they develop into complete embryos. This is because the fates of blastomeres are not predetermined in the early embryonic period. Vertebrates and certain invertebrates such as echinoderms which produce regulative type of eggs exhibit indeterminate cleavage.
