Answer: sensitive environmental indicators.
- A primary ecosystem producers
- B top-level apex predators
- C major soil decomposers
- D sensitive environmental indicators
Correct answer: D. sensitive environmental indicators
Explanation: Amphibians have permeable skin and are very sensitive to pollution and habitat change, so their decline serves as an early warning indicator of environmental degradation.
Concept context
Levels of biodiversity, species richness patterns, threats (HIPPO), and conservation strategies. Always in NEET.