Main substacne removed by haemodialysis is

Options

A. Ammonia
B. Uric acid
C. Urea
D. `H_(2)O`

Answer

### Step-by-Step Solution:

1. **Understanding Hemodialysis**: Hemodialysis is a medical procedure used to remove waste products and excess substances from the blood when the kidneys are not functioning properly.

2. **Identifying Waste Products**: The primary waste products that accumulate in the blood due to kidney malfunction include urea, ammonia, uric acid, and water.

3. **Recognizing Uremia**: When the kidneys fail, urea accumulates in the bloodstream, leading to a condition known as uremia. Uremia is harmful and can cause various health issues.

4. **Function of Hemodialysis**: During hemodialysis, blood is drawn from the body and passed through a dialysis machine (artificial kidney), where waste products are filtered out.

5. **Main Substance Removed**: Among the waste products, urea is the main substance that is specifically targeted and removed during the hemodialysis process.

6. **Conclusion**: Therefore, the main substance removed by hemodialysis is urea.

### Final Answer:
The main substance removed by hemodialysis is **urea**.

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