Explanation
- A
Lichens
Lichens are the classic bioindicators of air quality, especially sulphur dioxide. They are sensitive symbiotic associations of fungus and alga/cyanobacterium; many species vanish from polluted air. That is why (a) is the official key.
- B
Methyl mercury
Methyl mercury is a toxic pollutant (Minamata), not a living bioindicator organism. It is the poison, not the indicator species.
- C
Rose plant
A rose plant is not the textbook bioindicator of atmospheric pollution in this list.
- D
Sunflower
Sunflower is used in some phytoremediation talk, not as the well-known air-pollution bioindicator here.
Summary. Official key is (a) lichens. They signal SO2 and general air quality. Methyl mercury is a toxin, not an indicator organism; rose and sunflower are not the standard pair.
Same topic · past papers
UPPSC has asked this before
These previous-year questions sit on the same topic. Open one to practise the earlier ask.
-
2023 · Q111 · UPPGS
When was the Water (Prevention and Control of Pollution) Act enacted? -
2021 · Q111 · UPPGS
Which of the following is indicator of air pollution? -
2018 · Q142 · UPPGS
Which of the following energy sources produces NO atmospheric pollution? -
2025 · Q61 · UPPGS
With reference to lichens, which of the following statements is/are correct? 1. Lichens are very good indicators of pollution. 2. Lichens grow well in polluted areas. Select the correct answer from the code given below: -
2025 · Q70 · UPPGS
Which of the following prepared the Annual Groundwater Quality Report 2024 ? 1. Central Pollution Control Board 2. Central Water Commission) 3. Central Groundwater Board Select the correct answer from the code given below: