How do mollusks use a muscular foot and radula?

Mollusks utilize the muscular foot and the radula for distinct biological functions, primarily locomotion and feeding.

The Muscular Foot

The foot is a highly muscular organ used for movement, though its form and function vary by group:
* Gastropods: Typically possess a flat, muscular structure used for crawling. Waves of muscular contraction move the animal slowly across surfaces. In some species, the foot is modified into an adhesive disk or swimming lobes called parapodia.123
* Bivalves: Use a bladelike or tonguelike foot for burrowing into sand or mud. The animal extends the foot into the substrate, dilates the tip to anchor itself, and then uses pedal retractor muscles to pull the shell downward.41
* Cephalopods: In these mollusks, the foot is modified into a siphon or funnel used for jet propulsion.3

The Radula

The radula is a ribbonlike structure found in the mouths of most mollusks, with the notable exception of bivalves. It is covered in rows of small teeth called denticles and is supported by a cartilage-like mass known as the odontophore.56

Mollusks use the radula to feed by extruding it from the mouth and sliding it over the odontophore to scrape or rasp food particles from surfaces. Depending on the species, the radula may be used to drill into prey or even act as a harpoon to inject poison. As the teeth at the front wear down, the animal continuously produces new rows of denticles to replace them.56