The main area of various types of activities of a cell is

Which of the following is the smallest cell?

Explain the diversity found in the size,shape,and structure of cells.

What is seen in the cytoplasm?

$(P) \rightarrow$ Subatomic particles $\rightarrow$ Atoms $\rightarrow$ Molecules $\rightarrow (Q) \rightarrow$ Cells $\rightarrow$ Tissues. Which levels do $(P)$ and $(Q)$ represent in the given hierarchy of biological organization?

Size of a typical eukaryotic cell is