Ans.
Bacteria are unicellular, prokaryotic organisms, which belong to kingdom Monera. Bacteria exhibit a wide variety of shape and size and can be classified according to their shapes, such as rod-shaped, spherical, comma, spiral or corkscrew.
The diagram represents different bacterial cells with different size and shape. The light-green bacterial cells represent rod-shaped bacteria, the pink bacteria represent spiral bacteria, and the dark-green bacteria represent spherical bacteria.
Thus, the correct answer is 'option). which types of bacterium are in each sample?'