Assertion (A): Spleen is considered as one of the lymphoid organs.
Reason (R): Spleen helps in the formation of red blood cells.

Options

A. Both A and R are true and R is the correct explanation for A.
B. Both A and R are true, but R is not the correct explanation for A.
C. A is true and R is false.
D. A is false and R is true.

Explanation

To analyze the assertion and reason provided in the question, we can break down the statements step by step.

### Step 1: Understand the Assertion
The assertion states that "Spleen is considered as one of the lymphoid organs."
- The spleen is indeed classified as a lymphoid organ. Lymphoid organs are essential components of the immune system and are involved in the production and maturation of lymphocytes, which are crucial for the body's defense against pathogens.

### Step 2: Understand the Reason
The reason states that "Spleen helps in the formation of red blood cells."
- While the spleen does play a role in the lifecycle of red blood cells (erythrocytes), it is not primarily responsible for their formation. The primary site for the formation of red blood cells in adults is the bone marrow. The spleen acts more as a reservoir for red blood cells and helps in their recycling, especially during the breakdown of old or damaged erythrocytes.

### Step 3: Evaluate the Relationship Between Assertion and Reason
- The assertion is true because the spleen is indeed a lymphoid organ.
- The reason is somewhat misleading. While the spleen does have functions related to red blood cells, it does not directly help in their formation. Therefore, the reason does not correctly explain the assertion.

### Conclusion
Based on the analysis:
- The assertion (A) is true.
- The reason (R) is false because it does not accurately explain the assertion.

### Final Answer
The correct option is: "Assertion is true and reason is false."

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