Identify A, B, C and D from the following table regarding respiratory system :OrganismHabitatRespiratory organATerrestrialTracheal tubes and spiraclesScorpionsTerrestrialBSpongesCPlasma membraneTurtlesUnderwaterD

Answer: A – Insects (e.g. cockroach); B – Book lungs; C – Aquatic; D – Cloaca (cloacal respiration).

• A – Insects such as cockroach: terrestrial animals that breathe through a network of tracheal tubes opening outside by spiracles.
• B – Book lungs: scorpions (and spiders) breathe through book lungs.
• C – Aquatic: sponges live in water and exchange gases by simple diffusion across the plasma membrane of their body cells.
• D – Cloaca: turtles staying underwater absorb dissolved oxygen through the highly vascular cloacal sacs (cloacal respiration).