Biologists attribute the elevated species richness in tropical regions to several factors:
- Climate Stability: The consistently stable climate of tropical areas over extended durations facilitates the survival and evolutionary diversification of numerous species.
- Abundant Solar Energy: These regions benefit from high solar energy input, which boosts productivity and resource availability, thereby supporting a greater variety of species.
- Minimal Climatic Disruptions: In contrast to temperate zones, tropical environments endure fewer significant climatic disturbances, enabling continuous species evolution.

| List-I | List-II |
| A. Biodiversity hotspot | I. Khasi and Jantia hills in Meghalaya |
| B. Sacred groves | II. World Summit on Sustainable |
| C. Johannesburg South Africa | III. Parthenium |
| D. Alien species invasion | IV. Western Ghats |