`CO_(2)`combines with Hb to form :

Options

A. Carbaminohaemoglobin
B. Carboxy haemoglobin
C. Oxyhaemoglobin
D. Methaemoglobin

Answer

To solve the question "CO₂ combines with Hb to form:", we need to analyze the options provided and understand how carbon dioxide interacts with hemoglobin.

### Step-by-Step Solution:

1. **Understanding Hemoglobin (Hb)**: Hemoglobin is a protein in red blood cells responsible for transporting oxygen (O₂) from the lungs to the rest of the body and returning carbon dioxide (CO₂) from the tissues back to the lungs.

2. **Identifying the Options**:
- **Carbaminohemoglobin**: This is formed when carbon dioxide binds to hemoglobin.
- **Carboxyhemoglobin**: This is formed when carbon monoxide (CO) binds to hemoglobin, not carbon dioxide.
- **Oxyhemoglobin**: This is formed when oxygen binds to hemoglobin.
- **Methemoglobin**: This is a form of hemoglobin where iron is in the ferric state (Fe³⁺) and cannot bind oxygen.

3. **Analyzing the Interaction of CO₂ with Hb**:
- When CO₂ is produced in the tissues, it diffuses into the blood and can bind to hemoglobin. This binding forms carbaminohemoglobin, which helps transport CO₂ back to the lungs for exhalation.

4. **Conclusion**: Given the definitions and interactions, the correct answer to the question is **Carbaminohemoglobin**.

### Final Answer:
**CO₂ combines with Hb to form: Carbaminohemoglobin.**

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