can you explain mollusks??
98444
Fossil Groups - Mollusks  \nHome page for fossil mollusk studies at the U.S. Geological Survey ... What are Mollusks? Mollusks are an amazingly diverse group of animals that live in a wide variety of ... and the deep ocean. Some mollusks are excellent swimmers, others crawl or ...geology.er.usgs.gov/paleo/mollusks.
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i like their ink sacs!  and if you dissect one, they have a special pen (remnants of the shell in molluscs) that you can write with!  so fun!  \n\nps. there are seen in all squids
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invertebrate\n\nmore info at\nhttp://www.ipm.ucdavis.edu/WATER/U/ceriodaph.html
531506
Wikipedia says that it is unknown whether mollusks  possess a eucoelom, they have a hemocoel to facilitate blood movement however.
588153
This is going way back for me, but I thought that most crustaceans you had to actually dissect them before you could tell.  Sorry, I might be thinking of another class of animals.  I remember learning the answer to your question way back in junior high.
881260
I guess its because they eat different things- shells are essentially made up of certain things that the animal eats. Also, I guess from an evolutionary point of view, an animal ends up with either hard or soft shells based on the environment within which they live. They would need a hard shell if they were living in difficult surroundings where damage would be easily possible. So its more complex than you'd think! Good luck!
273965
Pearls are formed inside the shell of certain bivalve mollusks. As a response to an irritating object inside its shell, the mollusk will deposit layers of calcium carbonate (CaCO3) in the form of the minerals aragonite or calcite (both crystalline forms of calcium carbonate) held together by an organic horn-like compound called conchiolin. This combination of calcium carbonate and conchiolin is called nacre, or as most know it, mother-of-pearl.
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Pretty much like a series of wiggly lines across the page.  Often described as the trails of a herd (or whatever the collective pronoun is) of drunken snails.\n\nTo the inexperienced eye it looks like nothing but to someone who knows how to look at the traces it can show a great deal of information about the subsurface.  The trick is to lie the trace on a table and look along it rather than at it.  All of a sudden the picture is resolved.
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http://en.wikipedia.org/wiki/Shellfish
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just mast------ and try the start and stop method. as you feel your getting close, stop! get a drink of water etc. then start again it trains the mussels and body to last longer! Try it about five time a day.
269104
The Annelida have bilateral symmetry .The annelids also have a one-way digestive system . It has a segmented anterior with 8 hearts in each. It also has a body cavity. \n\nThe Mollusks are also bilateral like the annelids. They have a good nervous system. They also have a one-way digestive system. They have a coelom like the . The classes of mollusks are the bivalves, which have two valves, which the name suggests. It has 2 shells and 3 layers also. It has a mantle and it lives in the water. It has gills and abductor muscles. It has an excurrent and incurrent siphon, which no other phylum has. There are the gastropods, which live in land and ocean. It has one shell and one foot. There are also the cephalopods, which has tentacles a foot that can either be a sucker or hook.
908907
Shell for mollusks may be considered an exoskelaton.
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There are a few possible answers;\n-Some shells have holes in them because part of the creature's body protruded there; Keyhole limpets, for example.\n-Some shells may have been drilled by a parasite or a predator, for example, whelks have a rasped tongue-like organ called a radula - they use this to bore holes in the shells of other animals in order to devour them.\n-And some shells may simply have eroded naturally so as to have a hole in them.
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yes snails do have a digestive system they have mouth stomach and intestins and they do excrete waste\nI would tell you all the organs in their digestive system but I don`t know their names in english
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They're critters that permanently attach themselves to something and live out their lives there, like many sea creatures- usually they are motile as larvae and then settle on an object as an adult. Very few are sessile their entire lifespan but many many spend their adulthood that way.\n\nExamples- barnacles, sponges, corals\n\nWhen applied to plants (I assumed you meant animals, but just in case... ) it refers to leaves or stems that grow directly from the stem without a stalk.
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Use the Linnaeus System:\n\nKingdom Phylum Class Order Family Genus Species\n\nA way to remember it: Katie Put Clams On Fred's Giant Stomach. I learned it in HS Biology 30+ years ago and never have forgotten it.
402632
Probably many molluscs would make good environmental indicators (depending on what specific feature you are studying).  Most often I've heard of bivalves being used to indicate heavy metal pollution.  This is likely due to their method of feeding.  (Read more about Bivalves - http://en.wikipedia.org/wiki/Bivalve )\n\nHere is one example of how several molluscs were studied to see which was the best indicator of heavy metals:\n\n"The relationships between concentrations of the heavy metals Pb, Cd, Cu, Zn, Co, Ni, and Ag in nine bivalve molluscs (Arca ventricosa, Chama isotoma: Lithophaga teres. Pinctada margiritifera, Pycnodonte hyotis. Spondylus ducalis. Modiolus auriculatus, Trichomya hirsuta, Ustularca renuta) and their environment were studied."\n\nThere determinations were...\n\n"Accumulation of Pb and Cd by T. hirsuta was linear with time and increased in direct proportion to the external concentration of these metals. No loss of either metal was detected after 12 days in 'normal' seawater."\n\nFrom:  "Investigations of the potential of bivalve molluscs as indicators of heavy metal levels in tropical marine waters"  http://www.publish.csiro.au/nid/126/paper/MF9820285.htm\n\nFrom WikiPedia (in general):\n"Indicator species are unique environmental indicators as they offer a signal of the biological condition in a watershed or ecosystem, and are a warning system that pollution has entered the food web.\nThe term indicator species is a bit misleading, as indicators are often whole groups of flora/fauna types which can be used to assess environmental condition.  Most indicator species are fish, invertebrates, periphyton and macrophytes."\nhttp://en.wikipedia.org/wiki/Indicator_species\n\nCheers!