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• n  the inner germ layer that develops into the lining of the digestive and respiratory systems

• They are called endomorphic, mesomorphic and ectomorphic because the prominent features of each are derived, respectively, from the embryo's endoderm or inner layer (abdominal .
• From the first layer, known as the endoderm, will come the cells that line the gastrointestinal tract.

• entoderm
• endoblast
• entoblast
• hypoblast