Biodiversity and its Conservation Test 9

Species diversity is a measure of the diversity within an ecological community that incorporates both species richness (the number of species in a community) and the evenness of species abundances and it varies from region to region and mainly depends on rainfall apart from other other factors like temperature, light intensity etc. 

The 'Red Data Book' is the state document which is established for documenting rare and endangered species of animals, plants and fungi as well as some local subspecies that exist within the territory of the state or country. This book provides essential information for studies and monitoring programmes on rare and endangered species and their habits. 

Dioscorea is considered an endangered plant due to overexploitation.  This is a medicinal plant from the Himalayan region and it produces bulbil and rhizome and it is rich in steroidal compounds . Maize, Wheat, and rice are not used for medicinal purposes.

Extinction is the end of an organism or of a group of organisms, normally a species. Humans cause extinction of a species through over harvesting, pollution, habitat destruction, invasion of invasive species, over hunting and other influences. Although, earthquakes and diseases are the results of human activities but it does not cause any extinction of plant species. 

Therefore, the correct answer is option B.