🐾 Diversity in Living Organisms – Class 9 Science MCQs

Section 4: Animal Kingdom – Non-chordates to Chordates (Q76–Q100)

Q76. Which of the following is the simplest animal group?

A. Coelenterata
B. Porifera
C. Mollusca
D. Arthropoda

✅ Correct Answer: B. Porifera

Explanation:

• A. Coelenterates → More complex (tissues present).
• B. Correct, Porifera (sponges) = simplest animals, no tissues.
• C. Mollusca → Advanced, soft-bodied.
• D. Arthropoda → Very advanced invertebrates.

Q77. The body of sponges has:

A. Notochord
B. Pores
C. Segments
D. Tentacles

✅ Correct Answer: B. Pores

Explanation:

• A. Notochord = Chordates.
• B. Correct, sponges have pores (Porifera).
• C. Segments = Annelids.
• D. Tentacles = Coelenterates.

Q78. Which of the following shows tissue-level organization?

A. Sponges
B. Hydra
C. Earthworm
D. Man

✅ Correct Answer: B. Hydra

Explanation:

• A. Sponges → No tissues.
• B. Correct, Hydra (Coelenterata) → tissue level.
• C. Earthworm = organ-system.
• D. Man = advanced organ-system.

Q79. Which group has radial symmetry?

A. Arthropoda
B. Coelenterata
C. Annelida
D. Mollusca

✅ Correct Answer: B. Coelenterata

Explanation:

• A. Arthropoda = Bilateral.
• B. Correct, coelenterates (Hydra, Jellyfish) = radial symmetry.
• C. Annelids = Bilateral.
• D. Molluscs = Bilateral.

Q80. Which of the following is an acoelomate?

A. Planaria
B. Earthworm
C. Cockroach
D. Fish

✅ Correct Answer: A. Planaria

Explanation:

• A. Correct, flatworms (Platyhelminthes) = acoelomates.
• B. Earthworm (Annelid) = coelomate.
• C. Cockroach (Arthropod) = coelomate.
• D. Fish (Chordate) = coelomate.

Q81. Nematoda are also called:

A. Roundworms
B. Flatworms
C. Segmented worms
D. Ringworms

✅ Correct Answer: A. Roundworms

Explanation:

• A. Correct, Nematodes = roundworms (Ascaris).
• B. Flatworms = Platyhelminthes.
• C. Segmented worms = Annelids.
• D. Ringworm = Fungal disease.

Q82. Segmented body is characteristic of:

A. Mollusca
B. Annelida
C. Arthropoda
D. Echinodermata

✅ Correct Answer: B. Annelida

Explanation:

• A. Mollusca = Soft body.
• B. Correct, Annelids (Earthworm, Leech) → segmented body.
• C. Arthropoda = Segments fused into regions.
• D. Echinodermata = Radial symmetry.

Q83. Which phylum has jointed legs?

A. Annelida
B. Arthropoda
C. Mollusca
D. Echinodermata

✅ Correct Answer: B. Arthropoda

Explanation:

• A. No jointed legs.
• B. Correct, Arthropoda = jointed appendages (largest group).
• C. Molluscs = muscular foot.
• D. Echinoderms = spiny skin.

Q84. In which group is water vascular system present?

A. Echinodermata
B. Mollusca
C. Annelida
D. Arthropoda

✅ Correct Answer: A. Echinodermata

Explanation:

• A. Correct, water vascular system for locomotion (starfish).
• B. Molluscs → foot for movement.
• C. Annelids → muscles.
• D. Arthropods → legs.

Q85. Exoskeleton of arthropods is made of:

A. Calcium carbonate
B. Chitin
C. Silica
D. Protein

✅ Correct Answer: B. Chitin

Explanation:

• A. CaCO₃ → Molluscs (shell).
• B. Correct, arthropod exoskeleton = chitin.
• C. Silica = some sponges.
• D. Protein alone = not exoskeleton.

Q86. Which of the following are exclusively marine animals?

A. Mollusca
B. Echinodermata
C. Arthropoda
D. Annelida

✅ Correct Answer: B. Echinodermata

Explanation:

• A. Molluscs = both aquatic & terrestrial.
• B. Correct, echinoderms (starfish, sea urchin) = only marine.
• C. Arthropods = everywhere.
• D. Annelids = terrestrial + aquatic.

Q87. Notochord is present in:

A. Mollusca
B. Arthropoda
C. Chordata
D. Echinodermata

✅ Correct Answer: C. Chordata

Explanation:

• A. Molluscs = soft-bodied.
• B. Arthropods = exoskeleton.
• C. Correct, chordates have notochord at some stage.
• D. Wrong.

Q88. Which is not a vertebrate group?

A. Pisces
B. Amphibia
C. Reptilia
D. Arthropoda

✅ Correct Answer: D. Arthropoda

Explanation:

• A, B, C = Vertebrate classes.
• D. Arthropods are invertebrates.

Q89. Fish breathe with the help of:

A. Lungs
B. Gills
C. Skin
D. Spiracles

✅ Correct Answer: B. Gills

Explanation:

• A. Lungs = amphibians, mammals, reptiles.
• B. Correct, fish → gills.
• C. Amphibians (frogs).
• D. Spiracles = insects.

Q90. Amphibians differ from fishes because they:

A. Have gills
B. Lay eggs
C. Live both on land and water
D. Are cold-blooded

✅ Correct Answer: C. Live both on land and water

Explanation:

• A. Gills = fishes.
• B. Both lay eggs.
• C. Correct, amphibians → dual life (land + water).
• D. Both are cold-blooded.

Q91. Which group has scales and cold-blooded body?

A. Amphibia
B. Reptilia
C. Mammalia
D. Aves

✅ Correct Answer: B. Reptilia

Explanation:

• A. Amphibians = moist skin.
• B. Correct, reptiles (lizards, snakes) have dry scales.
• C. Mammals = warm-blooded.
• D. Birds = feathers + warm-blooded.

Q92. Which group of vertebrates have feather-covered body?

A. Aves
B. Mammals
C. Reptiles
D. Amphibians

✅ Correct Answer: A. Aves

Explanation:

• A. Correct, aves = birds with feathers.
• B. Mammals = hair.
• C. Reptiles = scales.
• D. Amphibians = moist skin.

Q93. Which vertebrates are warm-blooded?

A. Reptiles & Amphibians
B. Amphibians & Pisces
C. Aves & Mammals
D. Pisces & Amphibians

✅ Correct Answer: C. Aves & Mammals

Explanation:

• A, B, D → Cold-blooded.
• C. Correct, birds and mammals maintain constant body temperature.

Q94. Which class of animals have mammary glands?

A. Amphibians
B. Reptiles
C. Mammals
D. Aves

✅ Correct Answer: C. Mammals

Explanation:

• A, B, D → No mammary glands.
• C. Correct, mammals have mammary glands to nourish young.

Q95. Which vertebrate class lays eggs but is warm-blooded?

A. Amphibia
B. Reptilia
C. Aves
D. Mammalia

✅ Correct Answer: C. Aves

Explanation:

• A, B → Cold-blooded.
• C. Correct, aves lay eggs & are warm-blooded.
• D. Mammals (mostly) give birth to young.

Q96. Which vertebrate group gives birth to young ones?

A. Pisces
B. Amphibia
C. Reptilia
D. Mammalia

✅ Correct Answer: D. Mammalia

Explanation:

• A–C → Lay eggs.
• D. Correct, mammals = viviparous (except platypus).

Q97. Which chordate group includes humans?

A. Reptilia
B. Amphibia
C. Mammalia
D. Aves

✅ Correct Answer: C. Mammalia

Explanation:

• A. Reptiles → cold-blooded.
• B. Amphibians → moist skin.
• C. Correct, humans = mammals.
• D. Birds.

Q98. Which group has a four-chambered heart?

A. Amphibia and reptiles
B. Mammals and birds
C. Reptiles and amphibians
D. Pisces and reptiles

✅ Correct Answer: B. Mammals and birds

Explanation:

• A. Amphibians → 3 chambers, reptiles → mostly 3.
• B. Correct, birds & mammals = 4 chambers.
• C, D. Wrong.

Q99. Which animal is a mammal but lays eggs?

A. Whale
B. Kangaroo
C. Platypus
D. Elephant

✅ Correct Answer: C. Platypus

Explanation:

• A. Whale = mammal, gives birth.
• B. Kangaroo = pouched, live birth.
• C. Correct, platypus = egg-laying mammal (monotreme).
• D. Elephant = viviparous.

Q100. Which feature is common to all chordates?

A. Scales
B. Notochord
C. Mammary glands
D. Feathers

✅ Correct Answer: B. Notochord

Explanation:

• A. Scales → reptiles, fishes.
• B. Correct, all chordates have notochord at some stage.
• C. Mammary glands = mammals only.
• D. Feathers = birds only.

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