mollusc

Mollusca is a large phylum of invertebrate animals. The phylum Mollusca includes snails, slugs, clams, oysters, squid, and octopus. They are found in almost all environments, from the deepest oceans to freshwater habitats, and on land. Molluscs exhibit a wide range of body plans and adaptations. A common characteristic is a soft body, which in most species is protected by a shell. This shell is secreted by a specialized organ called the mantle. The shell can be external, internal, or absent in some groups. Many molluscs possess a muscular foot used for locomotion, or for anchoring. They often have a radula, a ribbon-like structure covered with tiny teeth, used for feeding. Respiration in aquatic molluscs typically occurs through gills, while terrestrial species may respire through a modified mantle cavity acting as a lung. Reproduction is diverse, with some species being hermaphroditic and others having separate sexes. Molluscs play significant ecological roles as herbivores, predators, and filter feeders, and are also an important food source for humans and other animals.