Question

Branchial respiration is observed in:

• A. Fishes
• B. Molluscs
• C.
  Aquatic arthropods
• D.
  All of the above

Answer 1

The correct option is D

All of the above
Branchial respiration means respiration through gills. Gills are special vascularised structures that are used as respiratory organs by aquatic arthropods and molluscs.
Among vertebrates, pulmonary respiration (through vascularised bags called lungs) is observed in amphibians, reptiles, aves, and mammals whereas fishes respire through gills. So, branchial respiration is observed in fishes, aquatic arthropods and molluscs.
Lower animals like sponges, coelenterates, and flatworms can use their entire body surface for gaseous exchange via simple diffusion. Insects have tracheal tubes as their respiratory organs. Earthworms and frogs can also respire through their moist skin.