Gastropods usually have a shell that they hide in when they sense danger. They move by sliding on a slimy, mocus substance thay they excrete. Ex. slugs and snails

Bivalves have one shell divided into two moving parts, called valves, which they close when they sense danger. They usually stay in one place. They eat small organisms that are in the water. Ex. mussels and clams

Invertebrates

Groups of Molluscs