What is the meaning of classification?

Match the names of branches of biology listed under column $I$ with the field of study given under column $II$; choose the answer which gives the correct combination of the alphabets of the two columns.
Column $I$ (Branch of biology) | Column $II$ (Field of study)
$A$ Palynology | $p$ Silkworms
$B$ Oncology | $q$ Pollens
$C$ Phycology | $r$ Cancer
$D$ Sericulture | $s$ Algae

Match the following columns and select the correct option based on the levels of biological organization and their corresponding scientific fields:

Column-$I$ (Scale)	Column-$II$ (Biological Level)	Column-$III$ (Science)
$a$. Macroscopic	$P$. Ecosystems	$i$. Physics
$b$. Submicroscopic	$Q$. Tissues	$ii$. Ecology
$c$. Conceptual	$R$. Organ systems	$iii$. Cytology
$d$. Microscopic	$S$. Subatomic particles	$iv$. Biology

What are the levels of organization with conceptual size shown in the figure below?

Study the four statements $(A-D)$ given below and select the two correct ones out of them.
$A.$ Definition of biological species was given by Ernst Mayr.
$B.$ Photoperiod does not affect reproduction in plants.
$C.$ Binomial nomenclature system was given by $R$.$H$. Whittaker.
$D.$ In unicellular organisms,reproduction is synonymous with growth.
The two correct statements are:

The scientific name $Rattus$ $rattus$ is an example of: