The number and types of organisms present on Earth refer to:

How many species of Amphibians are present in the Amazonian rain forest in South America?

Initially $A$ biodiversity hot spots were identified but subsequently nine more have been added to the list,bringing the total number of biodiversity hot spots in the world to $B$. These hot spots are the regions of accelerated habitat loss. Three of these hot spots—Western Ghats and Sri Lanka,Indo-Burma,and Himalaya—cover our country's exceptionally high biodiversity regions. Although all the biodiversity hot spots put together cover less than $C$ $\%$ of the earth's land area,the number of species they collectively harbour is extremely high,and the strict protection of these hot spots could reduce the ongoing mass extinctions by almost $D$ $\%$. $A, B, C$ and $D$ in the paragraph refer to:

The biodiversity increases when one moves from the pioneer to the climax stage. What could be the explanation?

What is the full form of $UNESCO$?

The historic Convention on Biological Diversity,'The Earth Summit' was held in Rio de Janeiro in the year