Which of the following cells of blastocyst acts as a precursor of the embryo ?

Options

A. Trophoblast
B. Inner cell mass
C. Stem cells
D. Both (B) & (C)

Answer

To solve the question "Which of the following cells of the blastocyst acts as a precursor of the embryo?" we will analyze the components of the blastocyst and identify which one is responsible for forming the embryo.

### Step-by-Step Solution:

1. **Understanding the Structure of the Blastocyst**:
- The blastocyst is a structure formed after the morula stage of development. It consists of two main parts: the outer layer called the trophoblast and an inner group of cells.

2. **Identifying the Components**:
- The **trophoblast** is the outer layer of the blastocyst that will eventually contribute to the placenta.
- The **inner cell mass (ICM)** is a group of cells located inside the blastocyst. This mass is crucial as it will develop into the embryo itself.

3. **Role of the Inner Cell Mass**:
- The inner cell mass is specifically designated to differentiate into the various tissues and organs of the embryo. Therefore, it acts as the precursor to the embryo.

4. **Conclusion**:
- Among the options given (trophoblast, inner cell mass, stem cells, both B and C), the correct answer is the **inner cell mass**. It is the only component that directly gives rise to the embryo.

### Final Answer:
The inner cell mass acts as a precursor of the embryo.

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