Which of the following is required for both laboratory and field studies?

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

Match the following columns:

Column-$I$	Column-$II$
$(A)$ Linnaeus	$(i)$ First discovered virus
$(B)$ Ivanowsky	$(ii)$ First discovered lichen
$(C)$ Iyengar	$(iii)$ Father of Indian Bryology
$(D)$ Tulasane	$(iv)$ Father of Taxonomy
$(E)$ Shiv Ram Kashyap	$(v)$ Father of modern Phycology in India

Why is the study of taxonomy performed?

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:

Choose the correct option for the following statements:
$(i)$ In $Homo$ $sapiens$,$Homo$ represents the genus/family.
$(ii)$ Museum/Zoological park is a place for living organisms.