Home / Topic 8 : Phylum-Mullusca NEET Style Questions

Question

Match the following. [NEET 2021]

Choose the correct answer from the options given below.
      A B C D
(a) 2 3 1 4
(b) 4 1 3 2
(c) 2 3 4 1
(d) 1 4 3 2

Answer/Explanation

Ans. (c)
(A) $-(2),(B)-(3,(C)-(4),(D)-(1)$
– Physalia belongs to phylum-Coelenterata (Cnidaria) and is commonly known as Portuguese man-of-war.
– Limulus belongs to phylum-Arthropoda and is a living fossil and commonly termed as king crab.
– Ancylostoma belongs to phylum-Aschelminthes and is commonly referred to as hookworm.
– Pinctada belongs to phylum-Mollusca and is commonly called pearl oyster.

Question

 In which one of the following, the genus name, its two characters and its phylum are not correctly matched, whereas the remaining three are correct? [CBSE AIPMT 2012]

Answer/Explanation

Ans. (a)
Option (a) is incorrect because molluscs are bilaterally symmetrical,
triploblastic, coelomate, soft bodied animals. Their soft body is covered by a calcareous shell and is unsegmented with a distinct head, muscular foot and visceral hump.
e.g. Pila(apple snail), Sepia(cuttle fish), Pinctada(pearl oyster), etc.

Question

 Which one of the following is a matching set of phylum and its three examples? [CBSE AIPMT 2006]

(a) Cnidaria – Bonellia, Physalia, Aurelia

(b) Platyhelminthes – Planaria, Schistosoma, Enterobius

(c) Mollusca – Loligo, Teredo, Octopus

(d) Porifera-Spongilla, Euplectella, Pennatula

Answer/Explanation

Ans. (c)

Loligo, Teredo and Octopus are the members of phylum-Mollusca.
Loligo is commonly called squid or sea arrow and is gregarious, fast swimmer in the open water of the sea and is carnivorous, feeding on crabs and fishes.
Octopus (devil fish) is found at the bottom of the sea. It is nocturnal and feeds on crabs, fishes and other molluscs.
Teredo or shipworm is a marine bivalve which has small anterior shell and long slender body with a small foot functioning as adhesive structure.

Question

 Closed circulatory system occurs in [CBSE AIPMT 1994]

(a) snail

(b) cockroach

(c) cuttle fish

(d) All of these

Answer/Explanation

Ans. (c)
Closed circulatory system occurs in cuttle fish, i.e. Sepia, cephalopods are the only molluscs with a closed circulatory system. They have two gill hearts (also known as bronchial hearts) that move blood through capillaries of the gill. A single systemic heart pumps the oxygenated blood through rest of the body.

Question

 Eye of the molluscan group that resembles vertebrate eye is [CBSE AIPMT 1992]

(a) Bivalvia

(b) Gastropoda

(c) Pelecypoda

(d) Cephalopoda

Answer/Explanation

Ans. (d)

Cephalopoda contains the most
specialised molluscs including squids, Octopus, cuttle fish. In these animals well developed eyes are present which resembles vertebrate eyes.

Question

 A wood boring mollusc/shipworm is [CBSE AIPMT 1988]

(a) Chiton

(b) Teredo

(c) Limax

(d) Patella

Answer/Explanation

Ans. (b)

Teredo comes under class-Pelecypoda (bivalvia). It is commonly known as ‘shipworm’. It is destructive to wood in sea water.

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