Which of the following is the function of lymph ?

Options

A. Transport oxygen to brain
B. Transport carbon dioxide to lungs
C. Return interstitial fluid back to the heart
D. Contain RBC, leukocytes and more proteins as compared

Answer

To solve the question regarding the function of lymph, we will analyze the options provided and determine which one correctly describes a function of lymph.

### Step-by-Step Solution:

1. **Understand the Role of Lymph:**
- Lymph is a fluid that is part of the lymphatic system. It plays a crucial role in maintaining fluid balance in the body and is involved in immune responses.

2. **Evaluate the Options:**
- **Option 1: Transport oxygen to the brain.**
- This function is primarily performed by blood, specifically red blood cells that carry oxygen.
- **Option 2: Transport carbon dioxide to the lungs.**
- Similar to oxygen transport, carbon dioxide is also transported by blood, particularly by red blood cells.
- **Option 3: Return interstitial fluid back to the heart.**
- This is a key function of lymph. Lymphatic vessels collect excess interstitial fluid (the fluid that surrounds cells) and return it to the bloodstream, thereby maintaining fluid balance.
- **Option 4: Contain RBC, leukocytes, and more protein compared to blood.**
- Lymph does not contain red blood cells (RBCs) in significant amounts; it primarily contains white blood cells (leukocytes) and proteins, but it is not a primary function.

3. **Identify the Correct Option:**
- Based on the evaluation, the correct function of lymph is to **return interstitial fluid back to the heart**.

### Conclusion:
The function of lymph is to return interstitial fluid back to the heart.

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