What is the structure labeled as $A$ in the given figure made of?

Find the correct set of structures/organelles not surrounded by membrane.

Plant cells differ from animal cells because of:

Which of the following organelles are membrane-bound?

Which structures participate in the formation of a cell?

In the given hierarchy of biological organization: $(P) \rightarrow \text{Subatomic particles} \rightarrow \text{Atoms} \rightarrow \text{Molecules} \rightarrow (Q) \rightarrow \text{Cells} \rightarrow \text{Tissues}$,what do $(P)$ and $(Q)$ represent respectively?