Suggest a reason as to why `CO` is poisonous.

Explanation

### Step-by-Step Solution:

1. **Understanding Carbon Monoxide (CO)**:
- Carbon monoxide is a colorless, odorless gas that is produced from incomplete combustion of carbon-containing fuels.

2. **Interaction with Hemoglobin**:
- Hemoglobin is a protein in red blood cells that is responsible for transporting oxygen from the lungs to the rest of the body.

...