The branch of biology which deals with the study of cell structure and function is known as:

Who observed that plants are composed of different kinds of cells?

Who first explained that new cells arise from the division of pre-existing cells?

Match column-$I$ (scientists) with column-$II$ (discovery) and select the correct option.

Column-$I$	Column-$II$
$A$. Leeuwenhoek	$I$. First saw and described a living cell
$B$. Robert Brown	$II$. Presence of cell wall is unique to plant cells
$C$. Schleiden	$III$. Discovered the nucleus
$D$. Schwann	$IV$. All plants are composed of different kind of cells

................examined a large number of .................and observed that all are composed of different kinds of cells which form the tissues.

The cell theory was proposed by $T. Schwann$. Who else proposed the cell theory?