Invagination of the Sea Urchin Blastula

Multiple Choice

Invagination of the sea urchin blastula

A) is preceded by changes in the shape of individual blastomeres.
B) involves the filopodia of secondary mesenchyme cells.
C) is due to the uneven distribution of various transcriptional regulatory proteins in the egg cytoplasm.
D) forms the archenteron.
E) All of the above