Different Results Are Achieved When an Eight-Cell Sea Urchin Embryo

Multiple Choice

Different results are achieved when an eight-cell sea urchin embryo is bisected horizontally as opposed to when it is bisected vertically.This observation supports which statement?

A) Cellular determinants are equally distributed in the embryo.
B) Differentiation has occurred by the eight-cell stage.
C) Inducers have determined cell fate by the eight-cell stage.
D) Polarity exists in the embryo by the eight-cell stage.
E) All cells of the eight-cell stage are totipotent.