Foetal membranes produced by trophoblast are

Options

A. Chorion and allantois
B. chorion and amnion
C. Amnion and allatois
D. Allantois an d yolk sac.

Answer

To answer the question about the fetal membranes produced by trophoblasts, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Trophoblasts**:
- The trophoblast is the outer layer of the blastocyst, which is a structure formed in the early stages of embryonic development. It plays a crucial role in implantation and forms part of the placenta.

2. **Identifying Fetal Membranes**:
- Fetal membranes are structures that develop to protect and support the embryo/fetus during pregnancy. The main fetal membranes include the chorion, amnion, allantois, and yolk sac.

3. **Role of Trophoblasts**:
- The trophoblast differentiates into two primary layers: the cytotrophoblast and the syncytiotrophoblast. These layers contribute to the formation of the chorion and the amnion.

4. **Chorion and Amnion**:
- The chorion is the outermost membrane that surrounds the embryo and contributes to the formation of the placenta. The amnion is the membrane that encloses the amniotic cavity, providing a protective fluid-filled environment for the developing fetus.

5. **Evaluating Answer Choices**:
- A. Chorion: Correct, as it is produced by the trophoblast.
- B. Allantois: Although it is a fetal membrane, it is not directly produced by the trophoblast.
- C. Amnion: Correct, as it is also produced by the trophoblast.
- D. Elantoids and Yolk sac: These are not produced by the trophoblast.

6. **Conclusion**:
- Based on the analysis, the fetal membranes produced by the trophoblast are the chorion and amnion. Therefore, the correct answer is **Option B: Chorion and Amnion**.