Question

multiple choice question
what is the name of the extraembryonic membrane that forms the outermost layer around the fetus and contributes to the formation of the placenta?
allantois
chorion
zona pellucida
yolk sac

Explanation:

• The allantois is involved in waste storage and blood vessel development but is not the outermost layer.
• The chorion is the outermost extra - embryonic membrane. It contributes to the formation of the placenta (in mammals, the placenta is formed from the chorion and the uterine wall).
• The zona pellucida is a membrane around the oocyte, not an extra - embryonic membrane.
• The yolk sac is important for early nutrient supply in some embryos but is not the outermost layer.

Answer:

Chorion