Amnion surrounds

Options

A. Allantois
B. Chorion
C. Embryo
D. Yolk sac.

Answer

**Step-by-Step Solution:**

1. **Understanding the Amnion**: The amnion is a thin, protective membrane that forms part of the amniotic sac during embryonic development.

2. **Location of the Amnion**: The amnion surrounds the developing embryo. It is one of the membranes that encase the embryo.

3. **Function of the Amnion**: The amnion is filled with amniotic fluid, which provides a cushioning effect and protects the embryo from physical shocks and injuries.

4. **Amniotic Sac**: When the amnion is filled with amniotic fluid, it is referred to as the amniotic sac. This sac plays a crucial role in maintaining a stable environment for the embryo.

5. **Other Membranes**: The amnion is one of three main membranes (or cavities) in the embryo's development. The other two are the chorion and the yolk sac.

6. **Allantois**: The allantois is an extension of the posterior wall of the yolk sac and is involved in waste management and gas exchange for the embryo.

7. **Conclusion**: Therefore, the amnion surrounds the embryo, providing protection and support during its development.

**Final Answer**: The amnion surrounds the embryo.

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