How many biodiversity hot spots have been identified in the world?

Assertion : Diversity observed in the entire geographical area is called gamma diversity.
Reason : Biodiversity decreases from high altitude to low altitude.

Diversity index commonly used in ecological studies is

What is the difference between flora, fauna, and vegetation? Eichhornia crassipes is called an exotic species, while Rauwolfia serpentina is an endemic species in India. What do these terms 'exotic' and 'endemic' refer to?

Which one of the following is not observed in biodiversity hotspots?

The ................ have a greater amphibian species diversity than the .......