Which scientist observed and described living cells for the first time?

The concept that new cells arise from pre-existing cells was proposed by whom?

Who proposed the statement '$Omnis cellula-e cellula$'?

The cell theory was proposed in the year $1839$ by Schleiden and Schwann. According to this theory,all organisms are composed of cells,and cells are the basic unit of life. How did this theory contribute to the field of science?

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

Column $X$	Column $Y$
$(1)$ Robert Brown	$(P)$ Final shape of cell theory
$(2)$ Virchow	$(Q)$ Bacterial staining method
$(3)$ Gram	$(R)$ Unit membrane concept
$(4)$ Robertson	$(S)$ Discovery of nucleus

Who coined the term "cell"?