> Which of the following animals isn't considered a type of mollusk?Considering snail, clam, octopus and lobster, the answer is: lobster. One intimidating example of a mollusk: the octopusA mollusk is an invertebratethat has a soft body. This animal group is one of the most diverse groups in theanimal kingdom, with nearly 100,000 different species. Examples include thesquid, octopus, clams, oysters, and snails.Generally speaking, mollusks are essential elements of their food chain andecosystem. They can be hosts for smaller organisms, filters for fresh andsaltwater, and have played important roles in human culture for thousands ofyears. One species of mollusk, known as a Cephalopod, has been recorded infossil form dating back as far as 500 million years ago. Since then, molluskslike the Cephalopod have played important roles in fishing industries and foodconsumption. In such a highly varied species, there are few definitions that fit allcategories. Mollusks can range from too small for visible sight, to as long as45 feet in length. Their lifespans can range from several hours to hundreds ofyears -- one species of mollusk has been recorded for living over 500 years.Mollusks account for 23% of all recorded marine life. Check out the video below to learn more.