In which stage does the embryo differentiate into trophoblast and an inner group of cells ?

Options

A. Gastrula
B. Neural
C. Blastula
D. Morula

Answer

To solve the question "In which stage does the embryo differentiate into trophoblast and an inner group of cells?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Embryonic Development Stages**:
- The embryonic development begins with the fertilization of the egg, forming a zygote.
- The zygote undergoes repeated mitotic divisions to form a solid ball of cells known as the morula.

2. **Identifying the Next Stage**:
- After the morula stage, the next significant stage in embryonic development is the blastula stage.
- During this stage, the cells begin to arrange themselves into two distinct layers.

3. **Differentiation into Trophoblast and Inner Cell Mass**:
- In the blastula stage, the outer layer of cells is called the trophoblast, while the inner group of cells is referred to as the inner cell mass.
- The trophoblast will eventually contribute to the formation of the placenta, while the inner cell mass will develop into the embryo itself.

4. **Conclusion**:
- Therefore, the correct answer to the question is that the embryo differentiates into the trophoblast and an inner group of cells during the **blastula stage**.

### Final Answer:
- The embryo differentiates into trophoblast and an inner group of cells during the **blastula stage**.