This undifferentiated embryonic structure then undergoes a phase of major cell migration called gastrulation, producing a gastrula with three separate germ layers: the endoderm, mesoderm, and ectoderm. Endoderm The endoderm is formed from cells that migrate toward the center of the developing gastrula.
The Eiffel tower is made of puddled iron. It is made up of steel in steel X's. The Eiffel Tower is made of iron. The Eiffel Tower is made of pure iron.
The Eiffel Tower is 984 feet tall and consists of an iron framework supported on four masonry piers, from which rise four columns that unite to form a single vertical tower. Platforms, each with an observation deck, are at three levels.