Question 62

(Multiple Choice)

In humans,identical twins are possible because


A)of the heterogeneous distribution of cytoplasmic determinants in unfertilized eggs.
B)of interactions between extraembryonic cells and the zygote nucleus.
C)of convergent extension.
D)early blastomeres can form a complete embryo if isolated.
E)the grey crescent divides the dorsal-ventral axis into new cells.

Answer