The umbilical cord attaches the embryo to the placenta.
The amnion is the membrane that contains the amniotic fluid.
The amniotic fluid acts as a shock absorber to the developing embryo. The placenta establishes a connection between the embryo and the mother. It carries oxygen, water and food from the mother's blood to the embryo's blood. It also removes waste products like urea and carbondioxide from the embryo's blood and put it into the mother's blood for elimination