What is the full form of $IUCN$?

How many more hotspots have been added in the list of biodiversity?

Identify the correct statements :
$1.$ According to $\text{IUCN} (2004)$,the total number of described species is slightly more than $1.5$ million.
$2.$ Robert May estimated the total species diversity on Earth to be around $7$ billion.
$3.$ Insects make up more than $70 \%$ of all recorded animal species.
$4.$ India,with $2.4 \%$ of the world's land area,contributes $8.1 \%$ to global species diversity.

Define/Explain: $\gamma$-diversity.

What is the difference between endemic and exotic species?

The Amazon rainforest in South America is home to the greatest number of which species?