Just Prior to the Onset of Gastrulation in an Embryo

Multiple Choice

Just prior to the onset of gastrulation in an embryo, the "organizer" cells are specified. What would you expect in the developing embryo if the specification of these cells were experimentally blocked?

A) There would be no effect on development.
B) Gastrulation would not occur, and normal development would cease.
C) The body axes would develop normally, but the embryo would not grow appendages.
D) The embryo would not develop an intestine, but all other organs and tissues would develop normally.