What is true for $X$ in the figure representing the species-area relationship?

What does '$W$' represent in the given figure?

Mangrove vegetation is found in

Match the columns:

Column-$I$	Column-$II$
$(i)$ Nile perch in Lake Victoria	$(i)$ Obvious reasons for habitat destruction
$(ii)$ Narrowly utilitarian	$(ii)$ Habitat destruction
$(iii)$ Main cause for biodiversity loss	$(iii)$ High endemism
$(iv)$ Hotspot	$(iv)$ Alien species

In India, tropical wet evergreen rain forests are not found in:

Which of the following statement$(s)$ is/are correct?
$(i)$ Rich biodiversity is not essential for ecosystem health.
$(ii)$ The current rate of species extinction is $100$ to $1000$ times faster than the pre-human extinction rate.
$(iii)$ Steller's sea cow became extinct due to overexploitation by humans.
$(iv)$ Even if we combine all biodiversity hotspots,they cover less than $2 \%$ of the Earth's land area.
$(v)$ The rate of mass extinction can be completely reduced by strict protection of hotspots.