Assertion : Zona pellucida is glycoproteinous in nature and dissolved during the event of implantation .
Reason : The blastocyst , along with zona pellucida enters in decidua of uterus to protect itself from uterine acidic medium .

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion .
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False .
D. If both Assertion & Reason are False.

Answer

### Step-by-Step Text Solution:

1. **Understanding the Assertion**: The assertion states that "Zona pellucida is glycoproteinous in nature and dissolved during the event of implantation."
- The zona pellucida is indeed a glycoprotein layer that surrounds the plasma membrane of mammalian oocytes (eggs).
- It plays a crucial role in fertilization and must dissolve before implantation occurs.

2. **Confirming the Assertion**:
- The zona pellucida does dissolve during the implantation process.
- Therefore, the assertion is **true**.

3. **Understanding the Reason**: The reason states that "The blastocyst, along with zona pellucida, enters in decidua of uterus to protect itself from uterine acidic medium."
- The blastocyst is the stage of the embryo that forms after the fertilized egg divides and develops into a fluid-filled structure.
- The implantation process occurs when the blastocyst attaches to the uterine wall, specifically the decidua.

4. **Evaluating the Reason**:
- Before the implantation, the zona pellucida is dissolved, and the blastocyst does not carry the zona pellucida into the uterus.
- Therefore, the reason provided is **false** because the blastocyst does not enter the uterus with the zona pellucida.

5. **Conclusion**:
- Since the assertion is true and the reason is false, the correct answer is that the assertion is true but the reason is false.

### Final Answer:
The correct option is: **Assertion is true, but the reason is false.**

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