The separation between the inner cell mass and the trophoblast forms a fluid-filled chamber called the
A) chorion.
B) yolk sac.
C) allantois.
D) amniotic cavity.
E) placenta.

Question

Quizplus · Accepted Answer

The separation between the inner cell mass and the trophoblast forms the amniotic cavity, which is filled with fluid and eventually becomes the amniotic sac that surrounds and protects the developing embryo/fetus. This chamber is distinct from the yolk sac, which forms earlier in development and is involved in producing blood cells, and from the chorion, which is a membrane that contributes to the formation of the placenta. The allantois is another membrane involved in waste removal and gas exchange, but it does not directly contribute to the formation of the amniotic cavity.

The Separation Between the Inner Cell Mass and the Trophoblast