What does '$X$' represent in the given graph?

Match List $I$ with List $II$:

List $I$	List $II$
$A$. Robert May	$I$. Species-Area relationship
$B$. Alexander von Humboldt	$II$. Long term ecosystem experiment using outdoor plots
$C$. Paul Ehrlich	$III$. Global species diversity at about $7$ million
$D$. David Tilman	$IV$. Rivet popper hypothesis

Choose the correct answer from the options given below:

In the given pie chart,what do '$a$' and '$b$' represent respectively?

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

Which of the following statements are correct about the Amazon rainforest?
$I$. They are called the lungs of the planet.
$II$. They harbour probably millions of species.
$III$. They are the largest tropical rainforest in South America and have the highest biodiversity on Earth.
$IV$. They are being cut and cleared for cultivating soybeans or for conversion to grasslands for raising beef cattle.
Choose the correct option.

Find the wrongly matched pair.