Which of the following is not a part of the endomembrane system?

Match the columns and identify the correct option.

Column $I$	Column $II$
$A$. Thylakoids	$(i)$ Disc-shaped sacs in Golgi apparatus
$B$. Cristae	$(ii)$ Condensed structure of $DNA$
$C$. Cisternae	$(iii)$ Flat membranous sacs in stroma
$D$. Chromatin	$(iv)$ Infoldings in mitochondria

Which of the following pairs lacks a unit membrane?

Match the following.

Column-$I$	Column-$II$
$a$. Cristae	$i$. Flattened membrane sacs like structure present in stroma
$b$. Cisternae	$ii$. Infolding of mitochondria
$c$. Thylakoids	$iii$. Disc-shaped sacs
$d$. Kinetochores	$iv$. Disc-shaped structure present in chromosome

$A$ student wants to study cell structure using a light microscope with a $10 \times$ eyepiece and a $45 \times$ objective lens. Which of the following light sources should they use to obtain the best resolution?

What is the use of HeLa cells in cell biology?