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

Match the columns:

Column-$I$	Column-$II$
$(A)$ Endemism	$(i)$ Khasi and Jaintia hills,Meghalaya
$(B)$ Hotspot of India	$(ii)$ Advanced ex-situ conservation
$(C)$ Sacred groves	$(iii)$ Species found in a particular area only
$(D)$ Cryopreservation	$(iv)$ Zoological park and botanical garden
$(E)$ Ex-situ conservation	$(v)$ Western Ghats

$A$ - Loss of biodiversity in a region may lead to an increase in plant production.
$R$ - Loss of biodiversity in a region may lead to lowered resistance to environmental perturbations such as drought.

Identify $X, Y$ and $Z$ from the given pie charts representing global biodiversity of invertebrates and vertebrates:

If the Bengal tiger becomes extinct,then . . . . . . .

Given below is the representation of the extent of global diversity of invertebrates. What groups do the four portions $(a, b, c, d)$ represent respectively?