Show with specific examples that the structure of the respiratory organs of mollusks is determined by their habitat.

In molluscs, the respiratory system can be represented by gills or lungs. It depends on the environment in which the mollusk lives.

Aquatic molluscs breathe through their gills. These include all bivalves (examples: toothless, scallops, mussels) and cephalopods (squid, cuttlefish, nautilus, octopus), as well as sea (rapa) and some freshwater snails.

Land snails breathe with their lungs. Among them are the grape snail, Achatina, slugs.