## **Core Concept**
The spleen is an organ involved in filtering the blood and storing red blood cells. It plays a critical role in the immune system and blood regulation. The spleen's capacity to hold and filter blood is related to its role in storing red blood cells and platelets.

## **Why the Correct Answer is Right**
The spleen acts as a reservoir for red blood cells and platelets, holding about 300-500 mL of blood, which is roughly 10-15% of the total blood volume in a healthy adult. This stored blood can be released into circulation when needed, such as during times of increased oxygen demand or blood loss.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 1-5% is too low considering the spleen's role as a significant reservoir for blood cells.
- **Option B:** 20-25% is higher than the generally accepted percentage of total blood volume stored in the spleen.
- **Option D:** 30-35% is significantly higher than any recognized estimate of blood volume stored in the spleen.

## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that the spleen's ability to store and release blood helps regulate blood volume and can be crucial in compensating for acute blood loss. However, in cases of severe splenomegaly or certain diseases, the spleen's storage capacity can be significantly altered.

## **Correct Answer:** . 10-15%