29) The end of a zygote that contains less yolk : 1380974.
29) The end of a zygote that contains less yolk is the animal pole.
30) In general, the endoderm gives rise to tissues located deeper in the body than those from the ectoderm.
31) The blastocoel is the hollow cavity in the morula.
32) Cleavage includes the stage of development between the zygote and blastula.
33) The blastula is the stage of embryonic development in which cells migrate.
34) Gastrulation begins at the sea urchin blastula’s vegetal pole.
35) The mesoderm refers to the middle layer produced during gastrulation.
36) The blastula contains an internal structure called the archenteron.
37) The mouth is the last thing produced by growth of the archenteron through the sea urchin gastrula.
38) The archenteron is mostly made of the mesoderm.
