What is "mollusk"?

Mollusk refers to a diverse group of invertebrate animals that are found in a wide range of aquatic and terrestrial environments. They are characterized by a soft, unsegmented body that is often protected by a hard, calcareous shell. Mollusks include snails, slugs, clams, oysters, mussels, and squid, among others. They are an important part of the food chain for many animals and also play an important role in nutrient cycling in aquatic ecosystems. Mollusks have a variety of feeding habits and are adapted to different types of environments, making them an important group of animals for scientific study and ecological research.