It is known that exposure to carbon monoxide is harmful to animals because

Options

A. it reduces `C_(O)` transport
B. it reduces `O_(2)` transport
C. it increases `C_(2)` transport
D. it increases `O_(2)` transport

Explanation

### Step-by-Step Solution:

1. **Understanding Hemoglobin**: Hemoglobin is a protein found in red blood cells that is responsible for transporting oxygen throughout the body. It consists of globin (a protein) and heme (a pigment containing iron).

2. **Oxygen Binding**: Hemoglobin can easily bind with oxygen to form a complex known as oxyhemoglobin. This binding is reversible, allowing hemoglobin to pick up oxygen in the lungs and release it in tissues.

3. **Carbon Monoxide Interaction**: When carbon monoxide (CO) is present, it can bind to hemoglobin much more strongly than oxygen can. This forms a stable complex called carboxyhemoglobin.

4. **Loss of Affinity for Oxygen**: Because of the strong bond between carbon monoxide and hemoglobin, hemoglobin loses its ability to bind with oxygen. This means that even if oxygen is present, hemoglobin cannot transport it effectively.

5. **Consequences of CO Exposure**: The reduction in oxygen transport can lead to serious health issues, including suffocation (choking) and potentially death, as the body's tissues are deprived of the oxygen they need to function.

6. **Conclusion**: Therefore, exposure to carbon monoxide is harmful to animals because it reduces the transport of oxygen in the blood, leading to severe physiological consequences.

### Final Answer:
Exposure to carbon monoxide is harmful to animals because it reduces the transport of oxygen in the blood due to the strong binding of carbon monoxide to hemoglobin.

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