The measure of the variety of species and their relative abundance present within a region is referred to as

Exploration of molecular,genetic and species level diversity for novel products of economic importance is known as

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.

The total number of biodiversity hotspots in the world is

What are keystone species?

Describe biodiversity.