Carbon dioxide is carried in the blood mainly as

Options

A. Sodium bicarbonate
B. Potassium bicarbonate
C. Carbamino- hemoglobin
D. Dissolved gas in plasma.

Answer

To answer the question, "Carbon dioxide is carried in the blood mainly as," we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Carbon Dioxide in the Body**:
- Carbon dioxide (CO2) is a waste product produced by cells during metabolism. It needs to be transported from the tissues to the lungs for exhalation.

2. **Recognize the Transport Mechanism**:
- The blood plays a crucial role in transporting gases, including CO2, from the tissues to the lungs.

3. **Identify the Forms of Carbon Dioxide Transported in Blood**:
- CO2 is transported in three main forms:
- **Bicarbonate ions (HCO3-)**: Approximately 70% of CO2 is converted into bicarbonate ions in the blood.
- **Carbamino compounds**: About 20-25% of CO2 binds with hemoglobin to form carbaminohemoglobin.
- **Dissolved CO2**: A small percentage (5-7%) is transported in a dissolved state in the plasma.

4. **Determine the Main Form of CO2 Transport**:
- Since the question asks for the main form in which CO2 is carried in the blood, we focus on the largest percentage. The majority (around 70%) of CO2 is carried as bicarbonate ions.

5. **Select the Correct Answer**:
- The question provides options, and based on our understanding, the correct answer is that carbon dioxide is carried in the blood mainly as bicarbonate ions (HCO3-).

### Final Answer:
Carbon dioxide is carried in the blood mainly as bicarbonate ions (HCO3-).

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