Which of the Following is Not One of the Extraembryonic

Question

Which of the following is not one of the extraembryonic membranes?
A) yolk sac
B) amnion
C) allantois
D) chorion
E) umbilical cord

Accepted Answer

The umbilical cord is not an extraembryonic membrane. Instead, it connects the embryo/fetus to the placenta, which is an organ that forms from the chorion and facilitates nutrient and gas exchange between the developing embryo/fetus and its mother. The other choices (yolk sac, amnion, allantois, and chorion) are all extraembryonic membranes that play important roles in fetal development.