NEET2026ZoologyBreathing and Exchange of GasesActual
Sponges exchange O₂ with CO₂ by __________.
Options
- Agills
- Bsimple diffusion over their entire body surfaces
- Cmoist cuticle
- Dtracheal tubes
Correct answer
B. simple diffusion over their entire body surfaces
Step-by-step solution
Sponges, coelenterates, and flatworms exchange O₂ with CO₂ by simple diffusion over their entire body surfaces. Gills are used by most aquatic arthropods and molluscs. Earthworms use their moist cuticle for gas exchange. Insects have a network of tubes called tracheal tubes to transport atmospheric air within the body. Answer: simple diffusion over their entire body surfaces