Biodiversity refers to the variety of living organisms from all sources. It exists at genetic, species, and ecosystem levels. Key threats include habitat loss, pollution, and overexploitation. Conservation strategies include protected areas like national parks, sanctuaries, and biosphere reserves which practice in-situ conservation. Ex-situ methods involve conservation outside natural habitats, like zoos. India has high biodiversity as a megadiverse country and is home to two biodiversity hotspots, the Western Ghats and Eastern Himalayas, which face serious threats.