Foetal membrane that provides the first blood corpuscle for circulation in embryo is

Options

A. Trophoblast
B. Yolk sac
C. Amnion and allatois
D. Chroion.

Answer

To solve the question regarding which foetal membrane provides the first blood corpuscles for circulation in the embryo, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about the foetal membrane responsible for producing the first blood corpuscles in the embryo.

2. **Identify the Options**: The options provided are:
- A) Trophoblast
- B) Yolk sac
- C) Amnion
- D) Chorion

3. **Analyze Each Option**:
- **Trophoblast**: This layer is involved in the implantation of the embryo and forms part of the placenta but does not produce blood corpuscles.
- **Yolk Sac**: This is an early embryonic structure that provides nutrients and is responsible for the production of the first blood cells (corpuscles) in the embryo.
- **Amnion**: This membrane surrounds the embryo and contains amniotic fluid, providing cushioning but does not produce blood cells.
- **Chorion**: This outer membrane contributes to the formation of the placenta but is not responsible for the initial blood cell production.

4. **Conclusion**: Based on the analysis, the yolk sac is the foetal membrane that provides the first blood corpuscles for circulation in the embryo.

5. **Final Answer**: The correct answer is **B) Yolk sac**.