<prompt> At the end of week 2 of development day 14, what is the composition of the embryonic disk?Epiblast onlyEpiblast and hypoblastEctoderm and endodermEctoderm, mesoderm, and endoderm  <response>: The embryoblast consists of the two distinct cell layers epiblast and hypoblast at the end of development week 2 day 14 and forms the bilaminar embryonic disk. Second week is called week of 2 - 2 cavities- amniotic cavity and yolk sac cavity 2 type of embryoblast - Epiblast and hypoblast 2 type of trophoblast - Cytotrophoblast and Syncytial trophoblast Gastrulation - formation of 3 germ layers in week 3 