Question

during the development the vi aortic has been modified in mamnals​

Answer 1

Explanation:

Although amphibian gastrulation is considerably modified in comparison with that in animals with oligolecithal eggs (e.g., amphioxus and starfishes), an archenteron forms by a process of invagination. Such is not the case, however, in the higher vertebrates that possess eggs with enormous amounts of yolk, as do the reptiles, birds, and egg-laying mammals. Cleavage in these animals is partial (meroblastic), and, at its conclusion, the embryo consists of a disk-shaped group of cells lying on top of a mass of yolk.