Reliable bioindicators for air pollutants (SO2 and noxious gases) are:
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Answer: C. Lichens and mosses
Explanation
Lichens and mosses absorb atmospheric moisture and nutrients directly across their entire surfaces. Sulfur dioxide and toxic gases disrupt their metabolic processes very rapidly. Their high sensitivity makes them ideal biological indicators of air pollution. Lichens lack true roots or protective waxy cuticles, making them vulnerable to airborne toxins. Different lichen species exhibit varying thresholds of tolerance to sulfur dioxide pollution. Scientists map lichen diversity around industrial areas to monitor air quality changes.
Environmental agencies use bioindicators for low-cost assessments of urban and industrial air pollution. The absence of sensitive lichens often signals high atmospheric sulfur dioxide concentrations. Monitoring biological responses complements chemical air quality sensor networks. Ferns and Cycas are less sensitive to gaseous sulfur dioxide than crustose lichens. Green algae and aquatic liverworts primarily indicate water quality rather than air pollution. Neem trees and Eichhornia serve different ecological roles and are not primary air bioindicators.
- Subject
- Agriculture
- Category
- Forestry
- Topic
- —
- Difficulty
- medium
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