Earthworms exchange gases with their environment primarily through their _________.

Step-by-step solution

According to NCERT, earthworms use their moist cuticle for the exchange of gases. Lower invertebrates like sponges, coelenterates, and flatworms exchange gases by simple diffusion over their entire body surface. Insects have a network of tracheal tubes, while most aquatic arthropods and molluscs use gills. Answer: moist cuticle