Assertion (A): Endometrium is a mucosal tissue made up of two layers.
Reason (R): It is a inner lining of the uterus. Each month it thickens and renew itself, preparing for pregnancy.

Options

A. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion(A).
B. Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
C. Assertion (A) is true but reason (R) is false.
D. Assertion (A) is false but reason (R) is true.

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**: The assertion states that the endometrium is a mucosal tissue made up of two layers. To analyze this, we need to know what the endometrium consists of. The endometrium is indeed a mucosal lining of the uterus.

**Hint**: Recall the structure of the endometrium and its layers.

2. **Identifying the Layers of the Endometrium**: The endometrium is composed of two main components:
- The epithelial layer (which is columnar epithelium).
- The stroma (which is a layer of connective tissue).

This confirms that the assertion is correct as it mentions two layers.

**Hint**: Think about the types of tissues that make up the endometrium.

3. **Understanding the Reason (R)**: The reason states that the endometrium is the inner lining of the uterus, which thickens and renews itself each month in preparation for pregnancy. This is a well-known fact about the menstrual cycle.

**Hint**: Consider the menstrual cycle and how the endometrium changes in response to hormonal signals.

4. **Evaluating the Relationship Between Assertion and Reason**: Both the assertion and reason are true. The endometrium is indeed the inner lining of the uterus, and it undergoes cyclical changes in preparation for potential implantation of an embryo.

**Hint**: Reflect on how the reason supports the assertion.

5. **Conclusion**: Since both the assertion and reason are true, and the reason correctly explains the assertion, the answer to the question is that both the assertion and reason are true, and the reason is a correct explanation of the assertion.

**Final Answer**: Both assertion and reason are true, and the reason is a correct explanation of the assertion.

### Final Answer Choice:
- **Option 1**: Both assertion and reason are true, and reason is the correct explanation of assertion.