Question 1

Which of the following is a key distinguishing feature of mollusks that aids in their identification?

Accepted Answer

Presence of a hard shell made of calcium carbonate

Question 2

Chitons, belonging to the class Polyplacophora, have multiple plates on their dorsal surface. How many main plates are typically found on a chiton, and what is their function?

Accepted Answer

8 plates; they provide flexibility and protection

Question 3

Which structure in gastropods is used for feeding and is often described as a 'rasping tongue'?

Accepted Answer

Radula

Question 4

Bivalves lack a radula. What is the primary reason for this anatomical difference compared to other mollusks?

Accepted Answer

They are filter feeders and use cilia to move food particles

Question 5

Cephalopods are known for their advanced nervous systems. Which of the following best explains why complex behavior is more critical for cephalopods than for bivalves?

Accepted Answer

Cephalopods are active predators requiring rapid responses to environmental stimuli

Question 6

During squid dissection, you observe two fin-like structures on the posterior end. What is their primary function?

Accepted Answer

Stabilize the squid during swimming

Question 7

Nematodes are described as pseudocoelomates. What does this mean in terms of their body cavity structure?

Accepted Answer

They have a fluid-filled cavity not completely lined by mesoderm

Question 8

Which of the following is a major advantage of the thin and flexible internal pen in squid compared to a calcium carbonate shell?

Accepted Answer

Allows for greater speed and maneuverability

Question 9

Leeches produce several substances when feeding on hosts. Which combination is correct?

Accepted Answer

Anesthetic, anticoagulant, vasodilator

Question 10

Earthworms possess a clitellum. What is its primary function?

Accepted Answer

Secretes mucus that holds mating earthworms together and forms the cocoon for eggs

Question 11

Which equation best represents the process of gas exchange in bivalves?

Accepted Answer

$$\mathrm{O_2$\ (water) \rightarrow O_2$\ (blood) \rightarrow CO_2$\ (water)}$$

Question 12

Which of the following best describes the function of the adductor muscles in bivalves?

Accepted Answer

They hold the two shells together tightly

Question 13

Cephalopods use a siphon for movement. Which equation describes the force generated by jet propulsion?

Accepted Answer

$$F = m 	imes a$$

Question 14

Which of the following statements about nematode movement is correct?

Accepted Answer

Nematodes move by thrashing due to longitudinal muscles only

Question 15

What is the main function of the radula in gastropods?

Accepted Answer

Scraping food particles from surfaces

Question 16

Which of the following is a disadvantage of being monoecious (hermaphroditic) in annelids?

Accepted Answer

Increased risk of self-fertilization leading to reduced genetic diversity

Question 17

Which group of annelids is primarily responsible for swimming and respiration due to their well-developed parapodia?

Accepted Answer

Errantians (bristleworms)

Question 18

Which of the following best explains why bivalves are restricted to aquatic environments?

Accepted Answer

They rely on water flow for filter feeding and respiration

Question 19

Which structure in the squid is responsible for producing ink as a defense mechanism?

Accepted Answer

Ink sac

Question 20

Which of the following is true regarding the function of the gills in mollusks?

Accepted Answer

Gills are used for respiration, allowing gas exchange between water and blood

Study Guide: Invertebrate Animal Phyla – Mollusca, Nematoda, and Annelida

Study Guide - Practice Questions

Study Guide - Flashcards