_____ is highly hazardous to animal health but on plants, this gas does not seem to show adverse effect.

Options

A. CO
B. `CO_(2)`
C. `SO_(2)`
D. `NO_(2)`

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a gas that is highly hazardous to animal health but does not adversely affect plants.

2. **Analyzing the Options**:
- **Carbon Monoxide**: Known to be harmful to animals as it binds with hemoglobin in the blood, preventing oxygen transport. It does not show adverse effects on plants.
- **Carbon Dioxide**: Not harmful to either plants or animals; essential for photosynthesis in plants.
- **Sulphur Dioxide**: Harmful to both plants and animals; contributes to acid rain.
- **Nitrogen Dioxide**: Also harmful to both plants and animals; contributes to air pollution and acid rain.

3. **Identifying the Correct Answer**: Based on the analysis, Carbon Monoxide is the only gas that is hazardous to animal health but does not adversely affect plants.

4. **Conclusion**: Therefore, the answer to the question is **Carbon Monoxide**.

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