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 {y'-ful} Tower, an immense stucture of exposed latticework supports made of puddle iron, was erected for the Paris Exposition of 1889. The Prince of Wales (later King Edward VII of England) officiated at the ceremonial opening.