Why is spleen called blood bank of the body ?

Explanation

### Step-by-Step Solution:

1. **Understanding the Function of the Spleen**: The spleen is an organ located in the upper left part of the abdomen. It plays a crucial role in the body's immune response and blood filtration.

2. **Storage of Red Blood Cells (RBCs)**: One of the primary functions of the spleen is to store red blood cells. It acts as a reservoir for these cells, which are essential for transporting oxygen throughout the body.

3. **Emergency Situations**: In cases of emergencies, such as hemorrhage (excessive bleeding) or stroke, the body may require an immediate increase in red blood cells to maintain adequate blood supply and oxygen delivery to vital organs.

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