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 was built to serve as a gateway into the World's Fair held in Paris in 1889. Initially only built as a temporary structure, meant to last less than 20 years, it has since become one of the world's architectural wonders.