How is the placenta connected to the embryo?

Placenta:

1. The placenta is a round, flat organ, which is connected to the developing embryo by a tube called the umbilical cord.
2. The placenta aids in the transfer of oxygen and nutrients to the developing embryo.
3. Additionally, it is in charge of removing waste and carbon dioxide from the fetus.
4. Blood vessels occur in abundance in the placenta. It has villi that expand the surface area for nutrient absorption.
5. The presence of the placenta throughout pregnancy is a unique characteristic found only in mammals.