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Animal Kingdom — NEET Biology MCQs with Solutions
Free NEET Biology Animal Kingdom MCQs with step-by-step solutions covering Basis of Classification, Porifera, Coelenterata & Ctenophora, Platyhelminthes & Aschelminthes, Annelida & Arthropoda, Mollusca & Echinodermata. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — Basis of Classification · easy · theory
Animals with a body cavity lined by mesoderm on both sides are called:
A. Pseudocoelomates
B. Acoelomates
C. Coelomates ✓ Correct
D. Diploblastic
Solution: A true coelom is lined by mesoderm; acoelomates lack it and pseudocoelomates have a mesoderm not fully lining the cavity.
Q2 — Basis of Classification · easy · theory
An animal that can be divided into two equal halves by any plane passing through the centre shows:
A. Radial symmetry ✓ Correct
B. Metamerism
C. Asymmetry
D. Bilateral symmetry
Solution: Radial symmetry (e.g. Cnidaria, echinoderm adults); bilateral means only one plane divides it into mirror halves.
Q3 — Porifera · easy · theory
Poriferans (sponges) are characterised by a water-transport (canal) system and special flagellated cells called:
A. Choanocytes (collar cells) ✓ Correct
B. Cnidoblasts
C. Nephridia
D. Flame cells
Solution: Choanocytes line the spongocoel/canals and drive the water current used for food, gas exchange and waste removal.
Q4 — Porifera · easy · theory
Sponges are supported by a skeleton of:
A. Cartilage
B. Chitin
C. Bone
D. Spicules or spongin fibres ✓ Correct
Solution: The sponge body is supported by calcareous/siliceous spicules or a network of spongin fibres.
Q5 — Coelenterata & Ctenophora · easy · theory
The stinging cells (cnidoblasts) used for defence and capture of prey are characteristic of:
A. Ctenophora
B. Platyhelminthes
C. Coelenterata (Cnidaria) ✓ Correct
D. Porifera
Solution: Cnidoblasts/cnidocytes bearing nematocysts on the tentacles define the Cnidaria.
Q6 — Coelenterata & Ctenophora · easy · theory
Ctenophores move using eight external rows of:
A. Setae
B. Parapodia
C. Tube feet
D. Ciliary comb plates ✓ Correct
Solution: Ctenophores (sea walnuts/comb jellies) swim by beating eight rows of ciliated comb plates.
Q7 — Platyhelminthes & Aschelminthes · easy · theory
Platyhelminthes are commonly called ______ and their excretion is carried out by ______:
A. Ribbon worms; gills
B. Roundworms; nephridia
C. Flatworms; flame cells ✓ Correct
D. Segmented worms; Malpighian tubules
Solution: Flatworms are dorsoventrally flattened; osmoregulation/excretion is by protonephridia (flame cells).
Q8 — Platyhelminthes & Aschelminthes · easy · theory
Aschelminthes (e.g. Ascaris) are commonly called:
A. Comb jellies
B. Flatworms
C. Segmented worms
D. Roundworms ✓ Correct
Solution: Aschelminthes have a circular cross-section — the roundworms.
Q9 — Annelida & Arthropoda · easy · theory
Arthropoda is the ______ phylum in the animal kingdom (largest number of species):
A. Least diverse
B. Largest ✓ Correct
C. Smallest
D. Second smallest
Solution: Two-thirds of all named animal species are arthropods — the largest phylum.
Q10 — Annelida & Arthropoda · easy · theory
Locomotory organs in the earthworm (Annelida) are the:
A. Wings
B. Setae (and, in Nereis, parapodia) ✓ Correct
C. Tentacles
D. Tube feet
Solution: Annelids move using setae; the aquatic Nereis has lateral parapodia.
Q11 — Mollusca & Echinodermata · easy · theory
The rasping feeding organ found in the mouth of most molluscs is the:
A. Radula ✓ Correct
B. Nephridium
C. Madreporite
D. Osculum
Solution: The radula is a file-like rasping ribbon used in feeding by most molluscs.
Q12 — Mollusca & Echinodermata · easy · theory
Echinoderms possess a unique ______ used in locomotion, feeding and respiration:
A. Notochord
B. Malpighian tubule
C. Water vascular system (with tube feet) ✓ Correct
D. Radula
Solution: The water (ambulacral) vascular system with tube feet is exclusive to echinoderms.
Q13 — Hemichordata & Chordata (Basis) · easy · theory
The three fundamental chordate characters present at some stage are:
A. Radula, mantle and shell
B. Water vascular system and tube feet
C. Ventral solid nerve cord and open circulation
D. Notochord, dorsal hollow nerve cord, and pharyngeal gill slits ✓ Correct
Solution: All chordates possess a notochord, a dorsal hollow nerve cord, and paired pharyngeal gill slits at some life stage.
Q14 — Hemichordata & Chordata (Basis) · easy · theory
Hemichordates were once placed with chordates but are now a separate phylum because they possess only a:
A. Cranium
B. True notochord throughout life
C. Vertebral column
D. Rudimentary structure (stomochord), not a true notochord ✓ Correct
Solution: The "stomochord" of hemichordates is not a true notochord, so they are placed in a separate phylum near the echinoderm–chordate line.
Q15 — Vertebrate Classes · easy · theory
Jawless vertebrates such as Petromyzon (lamprey) and Myxine (hagfish) belong to:
A. Chondrichthyes
B. Amphibia
C. Osteichthyes
D. Cyclostomata ✓ Correct
Solution: Cyclostomata are the most primitive, jawless (Agnatha), ectoparasitic vertebrates with a circular sucking mouth.
Q16 — Vertebrate Classes · easy · theory
Cartilaginous fishes (sharks, rays) with placoid scales belong to:
A. Osteichthyes
B. Reptilia
C. Amphibia
D. Chondrichthyes ✓ Correct
Solution: Chondrichthyes have a cartilaginous endoskeleton, ventral mouth, placoid scales, and lack an air bladder.
Q17 — Basis of Classification · hard · theory
True segmentation (metamerism), where the body is serially divided both externally and internally, is FIRST clearly seen in:
A. Platyhelminthes
B. Porifera
C. Coelenterata
D. Annelida ✓ Correct
Solution: Annelids show true metameric segmentation; arthropods and chordates also show it, but it appears first in annelids.
Q18 — Basis of Classification · hard · theory
Which sequence correctly lists the grade of body organisation in increasing complexity?
A. Organ-system → organ → tissue → cellular
B. Tissue → cellular → organ-system → organ
C. Organ → tissue → cellular → organ-system
D. Cellular → tissue → organ → organ-system ✓ Correct
Solution: Porifera show cellular level; coelenterates tissue level; platyhelminths organ level; from Aschelminthes upward organ-system level.
Q19 — Porifera · hard · theory
Sponges are hermaphrodites and reproduce sexually by forming ______, and asexually by ______:
A. Conidia; sporulation
B. Seeds; budding
C. Larvae after internal fertilisation; fragmentation/gemmules ✓ Correct
D. External spores; binary fission only
Solution: Most sponges are bisexual with internal fertilisation and a larval stage; they also reproduce asexually by fragmentation/gemmules.
Q20 — Porifera · hard · theory
Examples Sycon, Spongilla and Euspongia belong to Porifera. Which statement is CORRECT?
A. They are mostly marine, asymmetrical or radially symmetrical, and sessile ✓ Correct
B. They are bilaterally symmetrical and free-swimming
C. They have a true coelom
D. They possess a nervous system
Solution: Sponges are mostly marine, sessile, and asymmetrical/radially symmetrical, lacking true tissues, coelom and nervous system.
Q21 — Coelenterata & Ctenophora · hard · theory
Bioluminescence (light emission) is a well-marked feature of:
A. Flatworms
B. Sponges
C. Ctenophores (e.g. Pleurobrachia, Ctenoplana) ✓ Correct
D. All cnidarians
Solution: Ctenophores are noted for bioluminescence; they lack cnidoblasts (a key difference from Cnidaria).
Q22 — Coelenterata & Ctenophora · hard · theory
Which cnidarian example correctly matches its predominant body form?
A. Physalia — polyp only
B. Meandrina — medusa
C. Adamsia (sea anemone) — polyp; Aurelia (jelly fish) — medusa ✓ Correct
D. Hydra — medusa only
Solution: Sea anemones/corals are polypoid; jelly fish are medusoid; colonial forms (Physalia) show both.
Q23 — Platyhelminthes & Aschelminthes · hard · theory
Sexual dimorphism (males and females distinct) is a notable feature of:
A. Poriferans
B. Aschelminthes (roundworms) ✓ Correct
C. Platyhelminthes only
D. Cnidarians
Solution: In roundworms, sexes are separate and often show clear dimorphism (e.g. male Ascaris smaller with a curved tail).
Q24 — Platyhelminthes & Aschelminthes · hard · theory
Which set of features is correct for Platyhelminthes?
A. Triploblastic, acoelomate, bilaterally symmetrical, organ-level ✓ Correct
B. Diploblastic, coelomate, radial
C. Acoelomate, radial, tissue-level
D. Triploblastic, coelomate, organ-system level
Solution: Flatworms are the first triploblastic, bilaterally symmetrical, acoelomate animals at the organ level of organisation.
Q25 — Annelida & Arthropoda · hard · theory
The circulatory system of arthropods is ______, whereas that of annelids is ______:
A. Both open
B. Open; closed ✓ Correct
C. Closed; open
D. Both closed
Solution: Arthropods have an open circulatory system (haemocoel); annelids have a closed circulatory system.
Q26 — Annelida & Arthropoda · hard · theory
Which set of animals are all arthropods of medical/economic importance?
A. Pheretima, Hirudinaria, Nereis
B. Asterias, Antedon
C. Aplysia, Pila, Octopus
D. Anopheles (mosquito), Apis (honey bee), Locusta (locust) ✓ Correct
Solution: Mosquito, honey bee and locust are arthropods; the second set are annelids and the others are molluscs/echinoderms.
Q27 — Mollusca & Echinodermata · hard · theory
Echinoderms are placed close to chordates in evolution because they are:
A. Acoelomate
B. Protostomes with a radula
C. Deuterostomes (blastopore forms the anus), like chordates ✓ Correct
D. Diploblastic
Solution: Echinoderms and chordates are deuterostomes (enterocoelous coelom), indicating a shared lineage distinct from protostomes (annelids/arthropods/molluscs).
Q28 — Mollusca & Echinodermata · hard · theory
Which pairing of animal and phylum is CORRECT?
A. Antedon — Mollusca
B. Octopus — Echinodermata
C. Sepia — Echinodermata
D. Pila (Apple snail) — Mollusca; Asterias (star fish) — Echinodermata ✓ Correct
Solution: Pila, Octopus, Sepia are molluscs; Asterias, Antedon (feather star), Echinus are echinoderms.
Q29 — Hemichordata & Chordata (Basis) · hard · theory
In Vertebrata, the notochord during development is ______ by a ______:
A. Converted into; gill slits
B. Replaced; cartilaginous or bony vertebral column ✓ Correct
C. Retained unchanged; nerve cord
D. Enlarged into; a stomochord
Solution: All vertebrates possess a notochord embryonically, which is later replaced by the vertebral column enclosing the nerve cord.
Q30 — Hemichordata & Chordata (Basis) · hard · theory
Which correctly distinguishes Cephalochordata from Urochordata?
A. Cephalochordates lose the notochord as adults
B. Urochordates have a persistent full-length notochord
C. Both have vertebral columns
D. In Cephalochordata the notochord extends from head to tail and persists throughout life ✓ Correct
Solution: In Amphioxus (Cephalochordata) the notochord runs the whole body length and persists lifelong, unlike urochordates.