Ans: The characteristics of phylum Mollusca are:Their body is split into the top , foot (a large organ used for locomotion) and visceral mass(all the organs are contained in this).Their head has an antennae with eyes.The mantle, that is a soft covering, covers the visceral mass.In most molluscs, the mantle cavity is covered by a calcareous shell.Their mouth features a rasping organ called a radula.They have an open circulatory system.They are dioecious and development is indirect.