उपर्युक्त परिच्छेद के आधार पर प्रतिपादित, निम्नलिखित में से कौन-सा कथन सर्वाधिक निर्णायक निष्कर्ष को सर्वोत्तम रूप से दर्शाता है ?
Read this question in English
Which one of the following statements best reflects the most critical inference that can be made from the passage given above?
(a) Low intensity light has more adverse effect on the plants as compared to high intensity light. · (b) Light pollution can have a permanent adverse impact on an ecosystem. · (c) White light is better for the flowering of plants as compared to the light of other colours. · (d) Proper intensity of light in an ecosystem is important not only for plants but for animals too.
उत्तर और व्याख्या · explanation in English
Answer: (b) प्रकाश प्रदूषण का किसी पारिस्थितिक तंत्र पर स्थायी रूप से प्रतिकूल प्रभाव पड़ सकता है ।
Artificial night lighting stopped a wild pea-family plant from flowering, and the aphids that feed on it declined because food ran short. The harm travels through the food chain, so the passage's widest valid inference is that light pollution can damage a whole ecosystem, not just one plant.
- ✗ (a) Only the low intensity amber light is reported; no high-intensity result is given, so this comparison cannot be made.
- ✓ (b) The light suppressed flowering and, through the food shortage, the aphid population — an effect across two links of the ecosystem. 'Can have' keeps it a possibility, and it is the only option that captures this chain.
- ✗ (c) The passage reports no effect of the white light on flowering, so nothing supports ranking white above other colours.
- ✗ (d) The passage never speaks of a 'proper' intensity of light; it shows that artificial light at night harmed plants and, through them, insects.
Remember · For the 'most critical inference', choose the option that covers the passage's whole cause-and-effect chain, not a comparison it never tested.
Question and answer: UPSC's official GS Paper II (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·