I WONDER - Do All Mollusks Have Shells?

The video tutorial explains the characteristics of snails and other mollusks, focusing on their mantles and shells. It describes bivalves like oysters and clams, highlighting their ability to open and close. The tutorial also covers the mobility of mollusks, detailing how they move using a foot and muscles. Finally, it discusses how mollusks without mantles, such as octopi and squids, use a funnel for jet propulsion.

What are some characteristics of mask shells?

Explain how some bivalves remain stationary.