Gastropods

The shell of a mollusc is secreted by the

• mantle

• head-foot

• coelom

• visceral mass

There are nearly _____ species of Cephalopods.

• 700

• 1000

• 65,000

• 200

The largest, most diverse class of Molluscs is

• Gastropoda

• Cephalopoda

• Bivalvia

• Polyplacophora

The octopus and nautilus belong to the class

• Cephalopoda

• Bivalvia

• Gastropoda

• Caudofoveata

The mollusc class with two shells is

• Bivalvia

• Cephalopoda

• Gastropoda

• Monoplacophora

Molluscs have ________ symmetry.

• bilareral

• radial

• they are asymmetrical

All but one class of molluscs have a(n) _____ circulatory system.

• open

• closed

• no system

The two body parts are the

• head-foot and visceral mass

• head-foot and mantle

• mantle and visceral mass

Most of the internal organs are included in the

• visceral mass

• head-foot

• mantle

A twisting of the visceral mass, mantle, and mantle cavity is called

• torsion

• triplobastic

• radula

• head-foot