How many of the following structures are membrane-bound?
Endoplasmic reticulum,Golgi apparatus,Ribosomes,Lysosomes,Mitochondria,Microbodies,Centrioles,Nucleolus,Vacuoles

Match the following.

$A$. Microfilament	$i$. Cellulose
$B$. Microtubules	$ii$. Cytoskeleton
$C$. Intermediate filament	$iii$. In cilia and flagella
$D$. Cell wall	$iv$. Durable protein

Select the correct match for $X$ and $Y$:

Column $X$	Column $Y$
$(1)$ Vacuole	$(P)$ Absent in human erythrocytes
$(2)$ Nucleus	$(Q)$ Perinuclear space absent
$(3)$ Nuclear envelope	$(R)$ Synthesis of $rRNA$
$(4)$ Nucleolus	$(S)$ Maintains turgor pressure in cells

Adult human $RBCs$ are enucleate. Which of the following statement$(s)$ is/are most appropriate explanation for this feature?
$(1)$ They do not need to reproduce.
$(2)$ They are somatic cells.
$(3)$ They do not metabolise.
$(4)$ All their internal space is available for oxygen transport.

Which of the following pairs regarding cell structure and its function is mismatched?

Which of the following organelles are membrane-less?