Which Statement About Gastrulation in Amphibians Is True

Multiple Choice

Which statement about gastrulation in amphibians is true?

A) Gastrulation increases the number of germ layers from one to three.
B) The inward movement of mesoderm and endoderm creates the blastocoel.
C) Mesoderm forms by epiboly.
D) Inwardly moving bottle cells create the dorsal lip of the blastopore.
E) Prior to invagination, cells flatten at the vegetal pole.