Both plants and animals are provided with

In the given figure,what do $a$ and $b$ represent respectively?

$A$ mature plant cell has which of the following components?

Genes present in the cytoplasm of eukaryotic cells are found in:

Match the scientists in Column-$I$ with their contributions in Column-$II$:

Column-$I$	Column-$II$
$1.$ Robert Brown	$p.$ Final shape of Cell Theory
$2.$ Virchow	$q.$ Bacterial staining method
$3.$ Gram	$r.$ Unit membrane concept
$4.$ Robertson	$s.$ Discovery of nucleus

Assertion $(X)$: The cell is a wonderful marvel of the world.
Reason $(Y)$: It converts nutrients into free energy and contains its own information in the form of genetic material.