Answer:
The correct answer is endoderm, mesoderm, and ectoderm respectively.
Explanation:
During gastrulation stage three-layered germinal layers forms in triploblastic animals. The three layers are known as - outer layer ectoderm, middle layer mesoderm, and the inner layer endoderm.
Later on, the digestive system rises from the endoderm, mesoderm rises to the circulatory system, and ectoderm differentiates to form the nervous system.
Thus the correct answer is Endoderm, mesoderm, and ectoderm respectively.
