The correct option is 1 only
Explanation
The geographical distribution of biodiversity and vegetation is primarily determined by climatic factors (temperature, precipitation, and solar energy) and physical factors (soil characteristics and relief). The interaction between the weathering mantle (soil) and climate dictates the type and density of vegetation in a region.
Statement-wise Analysis
- Statement 1 is Correct: The weathering mantle, which refers to the layer of loose, weathered rock and soil material covering the bedrock, serves as the fundamental basis for the diversity of vegetation. It provides the necessary medium, nutrients, and anchorage for plants. The depth and fertility of this mantle determine the capacity of the land to support various plant species.
- Statement 2 is Incorrect: Biodiversity is not richer in the polar regions; rather, it follows a latitudinal gradient where species diversity is generally highest at the equator (tropics) and decreases towards the poles. Polar regions have harsh climatic conditions (extreme cold, limited sunlight) that limit biological productivity and diversity, regardless of the level of human interference.
- Statement 3 is Incorrect: The input of solar energy plays a critical role in determining the diversity of vegetation. Solar energy drives photosynthesis, which is the basis of primary productivity. Regions with higher solar input and adequate moisture (such as the tropics) support greater biomass and species diversity compared to energy-deficit regions.
Key Takeaway: Biodiversity generally decreases from the equator to the poles due to climatic constraints. The weathering mantle acts as the physical foundation for vegetation, while solar energy and precipitation are the primary climatic drivers of biodiversity.