Which of the Following is Formed When the Chorionic Villi

Question

Which of the following is formed when the chorionic villi burrow into the endometrial lining?
A) Yolk sac
B) Placenta
C) Umbilical cord
D) Ductus venosus

Accepted Answer

The placenta is formed when the chorionic villi burrow into the endometrial lining. The yolk sac is responsible for early nourishment of the developing embryo before the placenta is fully formed. The umbilical cord connects the fetus to the placenta and the ductus venosus is a shunt that bypasses the liver in fetal circulation.