The most efficient respiratory structure used by free living protozoan is ________
body surface
gills
buccal cavity
spiracle
Correct answer is A
Protozoa do not have any organellae for the process of respiration. The limiting permeable membrane (body surface) acts as a respiratory surface.
The free molecular oxy¬gen from the surrounding media enters into the body by diffusion. Presence of a cyto¬chrome system has been demonstrated in protozoa.