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True/False
Indicate whether the sentence or statement is true or false.
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1. |
Mollusks must eat constantly because the functioning of their nephridia causes the disposal of useful molecules as well as of waste products.
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2. |
Unlike arthropods, mollusks are unsegmented; instead, they are divided into three regions.
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3. |
Mollusks have four distinct body parts: a foot, a head, a visceral mass, and a tail.
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4. |
In terrestrial snails, the mantle cavity functions as a simple lung.
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5. |
Most bivalves have separate sexes, but some are hermaphroditic.
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6. |
Due to the presence of a shell, all gastropods are capable of living on land for at least a portion of their lives.
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7. |
Since cephalopods have tentacles, they have no need for a radula.
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Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
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8. |
All of the following are characteristics of mollusks except that they have
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a.
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a pseudocoelomate body plan.
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c.
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a complete digestive tract.
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b.
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bilateral symmetry.
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d.
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an open circulatory system.
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9. |
The cilia of a trochophore larva
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a.
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allow attachment to the ocean bottom.
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b.
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create currents for drawing in food.
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c.
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cover the entire larval body.
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d.
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are necessary for reproduction.
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10. |
Trochophore larvae
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a.
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are found in molluscan life cycles.
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b.
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possess a belt of cilia around their bodies.
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c.
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occur in annelid life cycles.
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d.
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All of the above
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11. |
A characteristic structure found in many mollusks is the radula, which is involved in
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a.
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jet propulsion.
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c.
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eating.
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b.
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opening and closing of the shells.
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d.
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reproduction.
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12. |
All of the following are classes of the phylum Mollusca except
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a.
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bivalves.
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c.
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gastropods.
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b.
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cephalopods.
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d.
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pseudopods.
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13. |
The only mollusks that have a closed circulatory system are
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a.
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bivalves.
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c.
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chitons.
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b.
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cephalopods.
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d.
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gastropods.
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14. |
Refer to the illustration above. Which two organisms in the diagrams possess mantles?
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a.
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Organisms “A” and “C”
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c.
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Organisms “A” and “D”
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b.
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Organisms “B” and “C”
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d.
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Organisms “B” and “D”
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15. |
“Jet propulsion” is the usual means of locomotion in water for
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a.
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arthropods.
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c.
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cephalopods.
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b.
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echinoderms.
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d.
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annelids.
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16. |
Refer to the illustration above. The organism shown in this diagram is a
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a.
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bivalve.
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c.
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chiton.
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b.
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cephalopod.
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d.
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gastropod.
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17. |
Refer to the illustration above. This organism possesses a(n)
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a.
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simple lung.
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c.
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internal beak.
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b.
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closed circulatory system.
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d.
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open circulatory system.
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18. |
Refer to the illustration above. Movement of this organism is dependent upon the structure labeled
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a.
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“1.”
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c.
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“3.”
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b.
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“2.”
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d.
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None of the above
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19. |
Shells of mollusks
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a.
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may consist of one or more pieces.
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c.
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allow for the attachment of muscles.
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b.
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provide protection.
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d.
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All of the above
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20. |
Adductor muscles are responsible for
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a.
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moving the valves of bivalves.
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c.
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pumping the hearts of mollusks.
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b.
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extending the feet of mollusks.
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d.
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fanning the gills of aquatic mollusks.
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