. Describe the variations in shape and size of cells.
Cells are generally round or spherical in shape. However they can be cuboidal or columnar and some animal cells are long and branched as in nerve cells.Size may range from very small which can not be visible with the naked eye and are the order of 0.1 micron e.g. in bacteria, to large and long e.g. muscle cells in animals and fibers in plants.