Assertion : RBC membrane is highly flexible
Reason: The amount of external protein in the cytoplasmic face of membrane is more.

Options

A. if both Assertion & Reason are true and the reason in the correct explanation of the assertion, then mark(1).
B. if both Assertion & Reason are true and the reason in the correct explanation of the assertion, then mark(2).
C. if Assertion is the ture statement but Reason is false, then mark(3)
D. if both Assertion and Reaosn are false statements, then mark(4)

Answer

To solve the assertion-reason question regarding the flexibility of the RBC membrane, we will analyze both the assertion and the reason step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "RBC membrane is highly flexible."
- This statement is **true**. Red blood cells (RBCs) are known for their unique biconcave shape, which allows them to deform and squeeze through narrow capillaries. The flexibility of the RBC membrane is crucial for its function in transporting oxygen and carbon dioxide.

2. **Understanding the Reason**:
- The reason given is "The amount of external protein in the cytoplasmic face of the membrane is more."
- This statement is **false**. The flexibility of the RBC membrane is not primarily due to the amount of external protein. In fact, RBCs lack organelles and have a unique cytoskeletal structure that contributes to their flexibility. The membrane is composed of a lipid bilayer with proteins, but the assertion regarding the amount of external protein affecting flexibility is incorrect.

3. **Evaluating the Relationship**:
- The assertion is true, but the reason provided is false. Therefore, the two statements are not correctly related to each other.

4. **Conclusion**:
- Based on the evaluation, we conclude that the correct option is that the assertion is true, while the reason is false.

### Final Answer:
- The assertion is true, and the reason is false. Therefore, the correct choice is option 3.

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