<prompt> Fate of Inner cell mass in embryo development...Placentaamniotic membraneFetusExpelled out of developing embryo by 7 weeks  <response>: Cells of blastocyst differentiate into an outer trophoectoderm and inner cell mass. Just before implantation trophoectoderm fuher divided into: Cytotrophoblast Syncytiotrophoblast Placenta and fetal membrances are derived from trophoectoderm. Inner cell mass helps in the development of embryo proper. 