Which protects the embryo from external injury

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which structure protects the embryo from external injury. This indicates that we need to identify a protective layer or sac surrounding the embryo.

2. **Identifying the Options**: The options given are amnion, allantois, chorion, and yolk sac. We need to analyze each option to determine which one provides protection.

3. **Understanding the Amniotic Sac**: The embryo develops inside the mother's body and is enclosed in a structure known as the amniotic sac. This sac is crucial for the protection of the embryo.

4. **Function of the Amniotic Fluid**: The amniotic sac is filled with amniotic fluid. This fluid serves multiple purposes:
- It cushions the embryo, protecting it from mechanical shocks and external injuries.
- It prevents desiccation (drying out) of the embryo, ensuring a stable environment for development.

5. **Conclusion**: Based on the functions of the amniotic sac and the amniotic fluid, we can conclude that the amnion is the structure that protects the embryo from external injury.

6. **Final Answer**: The correct answer is **A) Amnion**.

---