Question 1

Animals with a body cavity lined by mesoderm on both sides are called:

Accepted Answer

Coelomates. A true coelom is lined by mesoderm; acoelomates lack it and pseudocoelomates have a mesoderm not fully lining the cavity.

Question 2

An animal that can be divided into two equal halves by any plane passing through the centre shows:

Accepted Answer

Radial symmetry. Radial symmetry (e.g. Cnidaria, echinoderm adults); bilateral means only one plane divides it into mirror halves.

Question 3

Poriferans (sponges) are characterised by a water-transport (canal) system and special flagellated cells called:

Accepted Answer

Choanocytes (collar cells). Choanocytes line the spongocoel/canals and drive the water current used for food, gas exchange and waste removal.

Question 4

Sponges are supported by a skeleton of:

Accepted Answer

Spicules or spongin fibres. The sponge body is supported by calcareous/siliceous spicules or a network of spongin fibres.

Question 5

The stinging cells (cnidoblasts) used for defence and capture of prey are characteristic of:

Accepted Answer

Coelenterata (Cnidaria). Cnidoblasts/cnidocytes bearing nematocysts on the tentacles define the Cnidaria.

Question 6

Ctenophores move using eight external rows of:

Accepted Answer

Ciliary comb plates. Ctenophores (sea walnuts/comb jellies) swim by beating eight rows of ciliated comb plates.

Question 7

Platyhelminthes are commonly called ______ and their excretion is carried out by ______:

Accepted Answer

Flatworms; flame cells. Flatworms are dorsoventrally flattened; osmoregulation/excretion is by protonephridia (flame cells).

Question 8

Aschelminthes (e.g. Ascaris) are commonly called:

Accepted Answer

Roundworms. Aschelminthes have a circular cross-section — the roundworms.

Question 9

Arthropoda is the ______ phylum in the animal kingdom (largest number of species):

Accepted Answer

Largest. Two-thirds of all named animal species are arthropods — the largest phylum.

Question 10

Locomotory organs in the earthworm (Annelida) are the:

Accepted Answer

Setae (and, in Nereis, parapodia). Annelids move using setae; the aquatic Nereis has lateral parapodia.

Question 11

The rasping feeding organ found in the mouth of most molluscs is the:

Accepted Answer

Radula. The radula is a file-like rasping ribbon used in feeding by most molluscs.

Question 12

Echinoderms possess a unique ______ used in locomotion, feeding and respiration:

Accepted Answer

Water vascular system (with tube feet). The water (ambulacral) vascular system with tube feet is exclusive to echinoderms.

Question 13

The three fundamental chordate characters present at some stage are:

Accepted Answer

Notochord, dorsal hollow nerve cord, and pharyngeal gill slits. All chordates possess a notochord, a dorsal hollow nerve cord, and paired pharyngeal gill slits at some life stage.

Question 14

Hemichordates were once placed with chordates but are now a separate phylum because they possess only a:

Accepted Answer

Rudimentary structure (stomochord), not a true notochord. The "stomochord" of hemichordates is not a true notochord, so they are placed in a separate phylum near the echinoderm–chordate line.

Question 15

Jawless vertebrates such as Petromyzon (lamprey) and Myxine (hagfish) belong to:

Accepted Answer

Cyclostomata. Cyclostomata are the most primitive, jawless (Agnatha), ectoparasitic vertebrates with a circular sucking mouth.

Question 16

Cartilaginous fishes (sharks, rays) with placoid scales belong to:

Accepted Answer

Chondrichthyes. Chondrichthyes have a cartilaginous endoskeleton, ventral mouth, placoid scales, and lack an air bladder.

Question 17

The tendency to concentrate sensory and nervous tissue at the anterior end (cephalisation) is characteristically associated with which type of body symmetry?

Accepted Answer

Bilateral symmetry. Cephalisation, the formation of a definite head, is linked with bilateral symmetry where the animal moves head-first, so sense organs and nerve centres get concentrated anteriorly.

Question 18

Coelenterates (cnidarians) exhibit which grade of body organisation?

Accepted Answer

Tissue level of organisation. In cnidarians the cells are arranged into definite tissues (division of labour) but they do not form organs, so they show the tissue level of organisation.

Question 19

In diploblastic animals, the undifferentiated jelly-like layer lying between the ectoderm and the endoderm is called the:

Accepted Answer

Mesoglea. Diploblastic animals have only two germ layers; the non-cellular gelatinous mesoglea lies between them. A true cellular mesoderm appears only in triploblastic animals.

Question 20

The water-transport (canal) system of sponges is mainly responsible for:

Accepted Answer

Food gathering, respiratory exchange and removal of wastes. The canal system circulates water through the sponge body, serving in food capture, gaseous exchange and excretion; sponges are sessile and have no nervous system.

Animal Kingdom — NEET Biology MCQs with Solutions

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