Question

What is the outer extraembryonic membrane that forms finger-like projections called villi and helps form the placenta?

A) Amnion

B) Chorion

C) Yolk Sac

D) Allantois

Answer 1

The outer extraembryonic membrane that forms finger-like projections called villi and helps form the placenta is the chorion.

Step-by-step explanation:

The outer extraembryonic membrane that forms finger-like projections called villi and helps form the placenta is the chorion. The chorion is a membrane formed by extraembryonic mesoderm and trophoblast. The chorion undergoes rapid proliferation and forms the chorionic villi, which invade the uterine lining and help form the fetal portion of the placenta.