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.

• A
  Only $1$ and $3$ are correct
• B
  Only $2$ and $4$ are correct
• C
  Only $1, 3$ and $4$ are correct
• D
  All statements are correct