Question

in the course of evolution, the development of organs in the mesodermal space between the digestive endoderm and the ectoderm as the basis for homeostasis is associated with: a) protostomes and Deuterostomes. b)just the protosomes such as the earthwarm. c) only the chordates like humans. d) only the deuterostomes such as the vertebrates. e) the porifera

Answer 1

The embryonic cells of earth worm continues to divide to form a hollow-like structure called blastula. One side of the hollow ball/blastula flattens and folds back to the inner side to form a pocket. Those cells which lines the pocket forms the endoderm which further gives rise to digestive tract. The clls remaining on the surface are called as ectoderms which give rise to skin and nervous system. The third layer of the embryo is the mesoderm, is derived from the cells that are migrated into the interior space between the endoderm and ectoderm.

Answer: B.