Question 1

Which of the following is a key difference between Lophotrochozoa and Ecdysozoa protostomes?

Accepted Answer

Lophotrochozoa grow incrementally, while Ecdysozoa grow by molting their exoskeleton.

Question 2

A marine biologist discovers a new animal with the following features: segmented body, paired jointed appendages, chitinous exoskeleton, and open circulatory system. To which phylum does this animal most likely belong?

Accepted Answer

Arthropoda

Question 3

Which of the following is NOT a characteristic of the phylum Porifera?

Accepted Answer

Radial symmetry

Question 4

Which group of mollusks is characterized by a closed circulatory system, a well-developed head, and jet propulsion?

Accepted Answer

Cephalopoda

Question 5

A researcher is studying an animal with a pseudocoelom, defined cell number, and a corona of cilia used for feeding and locomotion. This animal most likely belongs to which phylum?

Accepted Answer

Rotifera

Question 6

Which of the following adaptations was crucial for protostomes to successfully transition from aquatic to terrestrial environments?

Accepted Answer

Development of desiccation-resistant eggs

Question 7

Which of the following statements about annelids is TRUE?

Accepted Answer

They possess segmented bodies and closed circulatory systems.

Question 8

Which of the following best describes the feeding adaptation of bivalves?

Accepted Answer

They are suspension feeders using gills for both feeding and respiration.

Question 9

A scientist finds an animal with the following features: unsegmented body, pseudocoelom, only longitudinal muscles, and a tough cuticle that is molted. Which phylum does this animal belong to?

Accepted Answer

Nematoda

Question 10

Which of the following is a reproductive innovation found in protostomes that increases survival in terrestrial environments?

Accepted Answer

Desiccation-resistant eggs

Question 11

Which of the following is a characteristic unique to chelicerates among arthropods?

Accepted Answer

Presence of chelicerae (claw-like feeding appendages)

Question 12

Which of the following groups is most closely associated with the production of hirudin, an anticoagulant, and anesthetic as parasites?

Accepted Answer

Leeches (Annelida)

Question 13

Which of the following is a feature of the molluscan body plan that is responsible for secreting the shell when present?

Accepted Answer

Mantle

Question 14

Which of the following best explains why insects are the most diverse group of animals on Earth?

Accepted Answer

They have evolved wings and undergo metamorphosis, allowing them to exploit diverse habitats and resources.

Question 15

Which of the following is TRUE about the life cycle of most cnidarians?

Accepted Answer

They alternate between asexual polyp and sexual medusa stages.

Question 16

Which of the following is a defining feature of the phylum Platyhelminthes?

Accepted Answer

Acoelomate body plan

Question 17

Which of the following is a characteristic of polyplacophoran mollusks (chitons)?

Accepted Answer

Eight dorsal plates made of calcium carbonate

Question 18

Which of the following is a function of the coelom in worm-like protostomes?

Accepted Answer

Acts as a hydrostatic skeleton

Question 19

Which of the following statements about crustaceans is correct?

Accepted Answer

They possess two pairs of antennae and compound eyes.

Question 20

A patient is infected with a parasitic flatworm that requires multiple hosts to complete its life cycle, including a primary sexual host and a secondary asexual host. To which subgroup does this parasite most likely belong?

Accepted Answer

Trematoda

Protostome Animals: Diversity, Phylogeny, and Major Groups

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