Which of the following damages chloroplasts and reduces photosynthetic efficiency ?

Options

A. Peroxyacetyl nitrate
B. Carbon monoxide
C. Carbon dioxide
D. SPM

Answer

To answer the question "Which of the following damages chloroplasts and reduces photosynthetic efficiency?", we will analyze the potential pollutants and their effects on chloroplasts and photosynthesis.

### Step-by-Step Solution:

1. **Understanding Chloroplasts and Photosynthesis**:
- Chloroplasts are the organelles in plant cells where photosynthesis occurs. They contain chlorophyll, which captures light energy to convert carbon dioxide and water into glucose and oxygen.

2. **Identifying Potential Pollutants**:
- The question implies that we need to identify pollutants that can damage chloroplasts. Common pollutants include sulfur dioxide (SO₂), carbon monoxide (CO), carbon dioxide (CO₂), and PAN (peroxyacetyl nitrate).

3. **Evaluating Sulfur Dioxide**:
- Sulfur dioxide is known to cause damage to plant tissues, including chloroplasts. It can lead to reduced photosynthetic efficiency by affecting chlorophyll production and function.

4. **Considering PAN (Peroxyacetyl Nitrate)**:
- PAN is a secondary pollutant formed from reactions involving volatile organic compounds (VOCs) and nitrogen oxides (NOx). It can also damage chloroplasts and reduce photosynthetic efficiency.

5. **Examining Other Pollutants**:
- Carbon monoxide primarily affects respiration in animals but does not directly damage chloroplasts. Carbon dioxide, while a greenhouse gas, is not a pollutant in normal concentrations and does not damage chloroplasts. Suspended particulate matter can cause physical blockage but is not directly damaging to chloroplasts.

6. **Conclusion**:
- Among the pollutants discussed, both sulfur dioxide and PAN can damage chloroplasts. However, if sulfur dioxide is not listed as an option, then PAN is the correct answer.

### Final Answer:
The correct answer is **PAN (Peroxyacetyl Nitrate)**, as it is a secondary pollutant that damages chloroplasts and reduces photosynthetic efficiency.

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