Which option correctly identifies the parts labeled $a$ and $b$ in the given figure?

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

The father of Indian Cytology is ...........

Match the following columns:-
List-$I$ List-$II$
$(a)$ Cristae $(i)$ Flat membrane-bound sacs in stroma
$(b)$ Cisternae $(ii)$ Infoldings in mitochondria
$(c)$ Thylakoids $(iii)$ Disc-shaped sacs in Golgi apparatus
$(d)$ Kinetochores $(iv)$ Disc-shaped structures in chromosomes

Which of the following statements are correct?
$I$. $PPLO$ is the smallest cell.
$II$. Prokaryotic cells are smaller than eukaryotic cells.
$III$. Cell division in prokaryotic cells is slow.
$IV$. All bacteria show solitary and colonial forms.
$V$. Cell division in prokaryotic cells is very rapid.

Match column $I$ (cell type) with column $II$ (size) and choose the correct option.

Column-$I$ (Cell type)	Column-$II$ (Size)
$A$. Viruses	$I$. $1-2 \; \mu m$
$B$. $PPLO$	$II$. $10-20 \; \mu m$
$C$. Eukaryotic cell	$III$. About $0.1 \; \mu m$
$D$. Bacterium	$IV$. $0.02-0.2 \; \mu m$