What does each structure does during the germinal stage according to the brief below
The embryonic stage
The mass of cells now implanted in the uterus is called an embryo. The
embryonic stage lasts for the next six weeks, until the eighth week of
pregnancy. During this time, two critical ‘life support’ systems develop:
the placenta and the umbilical cord. The placenta is a complex organ
that allows nutrients to pass from the mother to the embryo through the
umbilical cord. The arteries in this cord carry oxygen and nutrients to the
embryo, and the veins carry waste products (such as carbon dioxide and
urea) from the embryo, to be disposed of by the mother’s body.
During this stage, the cells of the embryo multiply rapidly and begin to
differentiate into the kinds of cells that will eventually become the
organism’s various body parts and organs. By the end of the embryonic
stage of development, the embryo is about two centimetres long. Yet the
embryo’s heart is beating and it is recognisable as a human being (with
facial features, hands, feet, fingers, toes, etc.), and the essential organ
systems and the nerve cells of the spine have formed. The embryo is
contained in a sac within the mother’s uterus and is surrounded by
amniotic fluid, which cushions and protects the embryo.