Phylum Mollusca: The Molluscs

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3. Molluscs are the _________ largest phylum of animals with approximately 50,000 extant species.

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Molluscs are the second largest phylum of animals with approximately 50,000 extant species. This means that there is another phylum that has more species than molluscs.

Explanation

Molluscs are the second largest phylum of animals with approximately 50,000 extant species. This means that there is another phylum that has more species than molluscs.

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9. The genus Chiton is located in what class?

The genus Chiton is located in the class Polyplacophora. This is because Polyplacophora is the class that includes chitons, which are a type of marine mollusk. Chitons are characterized by their shell, which is composed of multiple plates or valves, and their ability to cling to rocks or other surfaces using a muscular foot. Therefore, it can be concluded that the correct answer is Polyplacophora.

Explanation

The genus Chiton is located in the class Polyplacophora. This is because Polyplacophora is the class that includes chitons, which are a type of marine mollusk. Chitons are characterized by their shell, which is composed of multiple plates or valves, and their ability to cling to rocks or other surfaces using a muscular foot. Therefore, it can be concluded that the correct answer is Polyplacophora.

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10. What is the genus of this species?

The genus of this species is Octopus because Octopus is a specific genus of cephalopods, which includes various species of octopuses.

Explanation

The genus of this species is Octopus because Octopus is a specific genus of cephalopods, which includes various species of octopuses.

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13. What is the genus of this species?

The genus of this species is Nautilus. In biological classification, the genus is a rank in the taxonomic hierarchy that groups closely related species. Nautilus is a genus of cephalopods that includes several species of marine mollusks.

Explanation

The genus of this species is Nautilus. In biological classification, the genus is a rank in the taxonomic hierarchy that groups closely related species. Nautilus is a genus of cephalopods that includes several species of marine mollusks.

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15. What carried out many functions, but protection of the soft body is the primary function?

The mantle is a layer of tissue found in mollusks that carries out various functions, including protection of the soft body. It acts as a cover for the internal organs and produces the shell in many mollusks. The mantle also plays a role in locomotion, respiration, and the secretion of mucus. Therefore, while the mantle carries out multiple functions, its primary function is the protection of the soft body.

Explanation

The mantle is a layer of tissue found in mollusks that carries out various functions, including protection of the soft body. It acts as a cover for the internal organs and produces the shell in many mollusks. The mantle also plays a role in locomotion, respiration, and the secretion of mucus. Therefore, while the mantle carries out multiple functions, its primary function is the protection of the soft body.

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20. What is the genus of this species?

Helix is the genus of this species. The question is asking for the genus of a particular species, and the answer provided is "Helix." In biological classification, the genus is a rank in the taxonomic hierarchy that groups together closely related species. Therefore, the correct answer indicates that the species in question belongs to the genus Helix.

Explanation

Helix is the genus of this species. The question is asking for the genus of a particular species, and the answer provided is "Helix." In biological classification, the genus is a rank in the taxonomic hierarchy that groups together closely related species. Therefore, the correct answer indicates that the species in question belongs to the genus Helix.

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22. Which region contains the feeding, special sensory, and locomotion structures?

The head-foot region contains the feeding, special sensory, and locomotion structures. This region is responsible for various functions such as eating, sensing the environment, and movement. It is typically found in organisms such as mollusks, where the head contains sensory organs and the foot is used for locomotion.

Explanation

The head-foot region contains the feeding, special sensory, and locomotion structures. This region is responsible for various functions such as eating, sensing the environment, and movement. It is typically found in organisms such as mollusks, where the head contains sensory organs and the foot is used for locomotion.

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23. All but the_________ have a rasping, tongue-shaped organ called the radula, which is used for feeding.

Bivalves are the only organisms mentioned in the question that do not have a rasping, tongue-shaped organ called the radula. The radula is used for feeding in most mollusks, including gastropods (snails and slugs), cephalopods (squids and octopuses), and chitons. Bivalves, on the other hand, have a different feeding mechanism where they filter feed by pumping water through their gills and trapping food particles. Therefore, bivalves are the correct answer in this case.

Explanation

Bivalves are the only organisms mentioned in the question that do not have a rasping, tongue-shaped organ called the radula. The radula is used for feeding in most mollusks, including gastropods (snails and slugs), cephalopods (squids and octopuses), and chitons. Bivalves, on the other hand, have a different feeding mechanism where they filter feed by pumping water through their gills and trapping food particles. Therefore, bivalves are the correct answer in this case.

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24. Most molluscs go through metamorphosis, producing larval forms such as a ____________ and __________.

The correct answer is "trochophore, veliger". Most molluscs go through metamorphosis and produce larval forms called trochophores and veligers. These larval forms are distinct stages in the development of molluscs, with trochophores being the earlier stage and veligers being the later stage.

Explanation

The correct answer is "trochophore, veliger". Most molluscs go through metamorphosis and produce larval forms called trochophores and veligers. These larval forms are distinct stages in the development of molluscs, with trochophores being the earlier stage and veligers being the later stage.

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27. The molluscan body is divided into two regions -- the _________ and _________.

The correct answer is "Head-foot, visceral mass". In mollusks, the body is divided into two main regions: the head-foot, which contains sensory organs and is responsible for locomotion, and the visceral mass, which contains the internal organs such as the digestive, reproductive, and circulatory systems. Therefore, the head-foot and visceral mass are the correct regions in which the molluscan body is divided.

Explanation

The correct answer is "Head-foot, visceral mass". In mollusks, the body is divided into two main regions: the head-foot, which contains sensory organs and is responsible for locomotion, and the visceral mass, which contains the internal organs such as the digestive, reproductive, and circulatory systems. Therefore, the head-foot and visceral mass are the correct regions in which the molluscan body is divided.

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