Answer
The bilaminar embryonic disc is connected to the trophoblast by the so-called connecting stalk which a band of extraembryonic mesodermal cells.
Work Step by Step
By the end of the second week of embryonic development the bilaminar embryonic disc becomes connected to the trophoblast by a band or stalk of extraembryonic mesodermal cells. The importance of this band of cells is that it will later develop to form the umbilical cord.
