Correct option is C
The correct answer is (c).
Lichens are universally recognized by environmental scientists as exceptionally sensitive biological indicators for atmospheric quality, specifically extremely vulnerable to trace sulfur dioxide (SO2) and hydrogen fluoride (HF) pollution.
They lack roots and a protective cuticle, forcing them to absorb their water and trace nutrients directly from the surrounding ambient air.
Information Booster
- Lichens are not single plants but a highly complex symbiotic relationship tightly coupling a photosynthetic algae (or cyanobacteria) with a structural fungus.
- Because they lack root systems or waxy protective cuticles, they absorb airborne heavy metals and lethal toxic gases indiscriminately like massive biological sponges.
- High concentrations of airborne SO2 vigorously attack the algal partner's delicate chlorophyll, completely destroying its vital capacity to photosynthesize.
- Urban "lichen deserts" are intensely polluted industrial zones completely devoid of any crustose or foliose lichen growth, starkly highlighting severe local air toxicity.
- Different species demonstrate highly specific tolerances; thick, bushy "fruticose" lichens require absolutely pristine air, while flat "crustose" types are slightly hardier.
- Hydrogen fluoride (HF) pollution, frequently emitted from massive aluminum smelters, triggers rapid catastrophic necrotic lesions across the entire lichen thallus.
- Biomonitoring heavily leverages these organisms as extremely cost-effective, long-term continuous "living sensors" for tracking shifting industrial plume dispersion.
- Orchids are highly specialized epiphytes incredibly sensitive to narrow microclimates and massive habitat destruction, but they are absolutely not standard bioindicators for specific atmospheric gaseous pollutants.
- Apricots are economically vital fruit trees; while their tender foliage can indeed show severe injury from intense acute chemical exposure, they are not universally classified as primary, highly sensitive bioindicator species.
- Loranthus is a highly invasive, hemiparasitic plant aggressively attacking tree branches; its survival primarily mirrors the overall health of its specific host rather than direct atmospheric purity.
- Recognizing precise biological warning signs is crucial for early detection long before sophisticated electronic air quality monitors register massive industrial anomalies.
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10 Questions
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