NEETZoologyBreathing and Exchange of Gases
Which of the following groups of animals exchange O₂ with CO₂ by simple diffusion over their entire body surface?
Options
- ASponges, coelenterates, and earthworms
- BSponges, coelenterates, and flatworms
- CCoelenterates, flatworms, and insects
- DSponges, flatworms, and aquatic arthropods
Correct answer
B. Sponges, coelenterates, and flatworms
Step-by-step solution
According to NCERT, lower invertebrates like sponges, coelenterates, and flatworms exchange O₂ with CO₂ by simple diffusion over their entire body surface. Earthworms use their moist cuticle for gas exchange. Insects have a network of tracheal tubes to transport atmospheric air within the body. Aquatic arthropods use special vascularised structures called gills. Answer: Sponges, coelenterates, and flatworms