How long should a refrigerator last? This questions is asked so many time, again and again. Most refrigerator keep operational more than 10 years. A survey conducted by the appliance magazine found out that 80% of refrigerators last 8-14 years.
There are 5 main classes of mollusks, and two smaller classes that most people have never heard of. The principle classes are: Gastropoda (gastropods) - snails, slugs, conchs, whelks, cowries, etc. Bivalvia (bivalves) - clams, mussels, oysters, cockles, scallops, etc. just now. Report Abuse. The living mollusks are placed into seven classes (some workers combine the Solenogastres and Caudofoveata into a single class called Aplacophora): Solenogastres Caudofaveata Polyplacophora Scaphopoda Cephalopoda Bivalvia Gastropoda There are over 50,000 different types of mollusks alive today.
For most mollusk, their shell is external including snails, scallops, oysters, clams and mussels. For other mollusk, like squid, and cuttlefish, they have a internal skeleton similarly to a shell. There are also some that do not have a shell at all, like octopus and slugs, with only a mantle for protection of organs.ollusks have a body without a cavity, has more than two layers of cell layers, tissues and organs. Mollusks are soft bodied animals with three main regions: head, visceral mass, and foot. The head of the mollusk contains the sense organs such as the brain. It has a pair of eyes, a mouth, sensory and nervous structures.