Zoology MCQs – Part 1 (Q1–Q25)

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Q1. Zoology is best defined as the study of:

A) Plants
B) Animals
C) Microorganisms
D) Fungi

✅ Answer: B) Animals
Explanation: Zoology is the branch of biology dealing with the scientific study of animals, their structure, physiology, classification, and evolution.

• A) Plants → studied in Botany.
• C) Microorganisms → studied in Microbiology.
• D) Fungi → studied in Mycology.

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Q2. The father of modern Zoology is:

A) Aristotle
B) Charles Darwin
C) Lamarck
D) Theophrastus

✅ Answer: A) Aristotle
Explanation: Aristotle is called the Father of Zoology because of his pioneering work in animal classification and comparative anatomy.

• B) Darwin → Father of Evolutionary Biology.
• C) Lamarck → Early evolutionist (inheritance of acquired characters).
• D) Theophrastus → Father of Botany.

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Q3. Which phylum is characterized by radial symmetry and a water vascular system?

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

✅ Answer: B) Echinodermata
Explanation: Echinoderms (starfish, sea urchins) show radial symmetry (in adults) and possess a unique water vascular system for locomotion and feeding.

• A) Arthropoda → bilateral symmetry, exoskeleton.
• C) Mollusca → bilateral symmetry, soft body.
• D) Annelida → segmented worms with bilateral symmetry.

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Q4. The largest phylum in the animal kingdom is:

A) Mollusca
B) Arthropoda
C) Annelida
D) Chordata

✅ Answer: B) Arthropoda
Explanation: Arthropoda (insects, crustaceans, spiders) form the largest phylum, comprising over 80% of known animal species.

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Q5. Which of the following is a diploblastic animal?

A) Hydra
B) Earthworm
C) Cockroach
D) Starfish

✅ Answer: A) Hydra
Explanation: Hydra (phylum Cnidaria) is diploblastic (two germ layers: ectoderm & endoderm).

• Earthworm (Annelida), Cockroach (Arthropoda), and Starfish (Echinodermata) are triploblastic.

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Q6. Which of the following animals is acoelomate?

A) Planaria
B) Earthworm
C) Cockroach
D) Octopus

✅ Answer: A) Planaria
Explanation: Planaria (Platyhelminthes) lacks a true body cavity (acoelomate).

• Earthworm (Annelida) → coelomate.
• Cockroach (Arthropoda) → hemocoel.
• Octopus (Mollusca) → coelomate.

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Q7. Which is the first phylum to show a true coelom?

A) Platyhelminthes
B) Annelida
C) Arthropoda
D) Mollusca

✅ Answer: B) Annelida
Explanation: Annelids (earthworm, leech) are the first group to have a true coelom lined with mesoderm.

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Q8. Which of the following is a cold-blooded animal?

A) Pigeon
B) Lion
C) Frog
D) Whale

✅ Answer: C) Frog
Explanation: Frogs (amphibians) are ectothermic (cold-blooded), their body temperature varies with the environment.

• Birds and mammals (pigeon, lion, whale) are warm-blooded.

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Q9. Which of the following is an example of an oviparous animal?

A) Whale
B) Bat
C) Hen
D) Kangaroo

✅ Answer: C) Hen
Explanation: Hens lay eggs, hence oviparous. Mammals like whales, bats, and kangaroos are viviparous.

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Q10. Which is the excretory organ of earthworm?

A) Flame cells
B) Malpighian tubules
C) Nephridia
D) Kidneys

✅ Answer: C) Nephridia
Explanation: Earthworms use nephridia for excretion.

• A) Flame cells → Platyhelminthes.
• B) Malpighian tubules → Insects.
• D) Kidneys → Vertebrates.

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Q11. Which blood cells in humans help in immunity?

A) RBCs
B) WBCs
C) Platelets
D) Plasma

✅ Answer: B) WBCs
Explanation: White Blood Cells (leukocytes) fight infections and provide immunity. RBCs transport oxygen, platelets help clotting, plasma carries nutrients.

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Q12. Which vertebrate group has a three-chambered heart?

A) Mammals
B) Amphibians
C) Birds
D) Crocodiles

✅ Answer: B) Amphibians
Explanation: Amphibians (frog, toad) have 3 chambers (2 atria + 1 ventricle).

• Mammals & birds → 4 chambers.
• Crocodiles → 4 chambers (exception among reptiles).

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Q13. Which animal shows metameric segmentation?

A) Earthworm
B) Octopus
C) Snail
D) Hydra

✅ Answer: A) Earthworm
Explanation: Earthworms (Annelida) show true metamerism (body divided into repeating segments).

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Q14. Which animal has a notochord throughout life?

A) Amphioxus
B) Frog
C) Human
D) Shark

✅ Answer: A) Amphioxus
Explanation: Amphioxus (Cephalochordata) retains notochord throughout life.

• Frogs, humans, and sharks → notochord replaced by vertebral column.

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Q15. The exoskeleton of arthropods is made of:

A) Cellulose
B) Chitin
C) Keratin
D) Collagen

✅ Answer: B) Chitin
Explanation: Arthropod exoskeleton is made of chitin, a tough polysaccharide.

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Q16. Which of the following is a cartilaginous fish?

A) Salmon
B) Shark
C) Tuna
D) Rohu

✅ Answer: B) Shark
Explanation: Sharks (Chondrichthyes) have a skeleton made of cartilage, unlike bony fishes (Osteichthyes: salmon, tuna, rohu).

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Q17. Which is the largest living bird?

A) Peacock
B) Eagle
C) Ostrich
D) Albatross

✅ Answer: C) Ostrich
Explanation: The ostrich (Struthio camelus) is the largest living bird.

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Q18. Which animal is called the “living fossil”?

A) Crocodile
B) Peripatus
C) Coelacanth
D) Lungfish

✅ Answer: C) Coelacanth
Explanation: The coelacanth, once thought extinct, is called a living fossil.

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Q19. Which is the respiratory organ in cockroach?

A) Gills
B) Lungs
C) Book lungs
D) Tracheae

✅ Answer: D) Tracheae
Explanation: Cockroaches breathe through a network of tracheae and spiracles.

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Q20. Which of the following is a mammal that lays eggs?

A) Dolphin
B) Platypus
C) Kangaroo
D) Whale

✅ Answer: B) Platypus
Explanation: Platypus is a monotreme, an egg-laying mammal.

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Q21. Which is the connective tissue that connects muscle to bone?

A) Ligament
B) Tendon
C) Cartilage
D) Adipose

✅ Answer: B) Tendon
Explanation: Tendons connect muscle to bone, while ligaments connect bone to bone.

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Q22. Which of the following animals has a four-chambered heart?

A) Frog
B) Crocodile
C) Turtle
D) Lizard

✅ Answer: B) Crocodile
Explanation: Crocodiles are unique reptiles with a four-chambered heart, unlike most reptiles (3 chambers).

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Q23. Which of the following is NOT a mammal?

A) Whale
B) Dolphin
C) Bat
D) Penguin

✅ Answer: D) Penguin
Explanation: Penguins are birds (Aves), not mammals.

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Q24. Which vitamin is produced by intestinal bacteria?

A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin D

✅ Answer: B) Vitamin B12
Explanation: Gut microbiota synthesizes Vitamin B12 and some vitamin K.

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Q25. The scientific name of housefly is:

A) Anopheles gambiae
B) Musca domestica
C) Aedes aegypti
D) Drosophila melanogaster

✅ Answer: B) Musca domestica
Explanation: Housefly → Musca domestica.

• Anopheles → malaria vector.
• Aedes → dengue vector.
• Drosophila → fruit fly, used in genetics.

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Zoology MCQs – Part 2 (Q26–Q50)

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Q26. The functional unit of the kidney is:

A) Nephron
B) Alveolus
C) Neuron
D) Glomerulus

✅ Answer: A) Nephron
Explanation: The nephron is the structural and functional unit of the kidney, responsible for filtration, reabsorption, and urine formation.

• B) Alveolus → lung unit.
• C) Neuron → nerve cell.
• D) Glomerulus → part of nephron (capillary tuft).

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Q27. Which of the following organisms exhibits alternation of generation?

A) Hydra
B) Obelia
C) Amoeba
D) Euglena

✅ Answer: B) Obelia
Explanation: Obelia (Cnidaria) shows alternation between polyp (asexual) and medusa (sexual) stages.

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Q28. Which of the following is a jawless fish?

A) Shark
B) Lamprey
C) Salmon
D) Tuna

✅ Answer: B) Lamprey
Explanation: Lamprey belongs to Agnatha, the jawless fishes.

• Sharks → cartilaginous fishes (Chondrichthyes).
• Salmon & tuna → bony fishes (Osteichthyes).

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Q29. The basic contractile unit of muscle is:

A) Sarcolemma
B) Sarcomere
C) Myofibril
D) Actin filament

✅ Answer: B) Sarcomere
Explanation: The sarcomere (between two Z-lines) is the functional contractile unit of striated muscle.

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Q30. Which of the following mammals is aquatic?

A) Whale
B) Elephant
C) Camel
D) Kangaroo

✅ Answer: A) Whale
Explanation: Whales are fully aquatic mammals with lungs, warm-blooded, and viviparous.

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Q31. Which of the following is an example of a marsupial?

A) Bat
B) Kangaroo
C) Dolphin
D) Whale

✅ Answer: B) Kangaroo
Explanation: Kangaroos are marsupials—mammals that give birth to underdeveloped young carried in a pouch.

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Q32. Which blood group is called the universal donor?

A) AB+
B) O-
C) A+
D) B-

✅ Answer: B) O-
Explanation: People with O negative blood can donate to all blood groups (universal donor).

• AB+ → universal recipient.

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Q33. The respiratory pigment in earthworm is:

A) Hemocyanin
B) Hemoglobin
C) Myoglobin
D) None

✅ Answer: B) Hemoglobin
Explanation: Earthworms have hemoglobin dissolved in plasma (not inside cells).

• Hemocyanin → Arthropods & mollusks.

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Q34. Which of the following is a poisonous snake?

A) Python
B) Cobra
C) Rat snake
D) Boa

✅ Answer: B) Cobra
Explanation: Cobra is venomous.

• Python, rat snake, boa → non-venomous.

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Q35. Which of the following has a 3-chambered heart with partial septum?

A) Crocodile
B) Lizard
C) Fish
D) Mammal

✅ Answer: B) Lizard
Explanation: Lizards (reptiles) have 3 chambers (2 atria + 1 ventricle) with incomplete septum.

• Crocodiles → 4 chambers.
• Fish → 2 chambers.
• Mammals → 4 chambers.

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Q36. Which of the following produces antibodies?

A) B-lymphocytes
B) T-lymphocytes
C) RBCs
D) Platelets

✅ Answer: A) B-lymphocytes
Explanation: B cells differentiate into plasma cells and produce antibodies.

• T cells → cell-mediated immunity.

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Q37. Which animal shows polymorphism?

A) Hydra
B) Amoeba
C) Obelia
D) Paramecium

✅ Answer: C) Obelia
Explanation: Obelia shows polymorphism—different forms (feeding polyp, reproductive polyp, medusa).

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Q38. Which is the heaviest flying bird?

A) Ostrich
B) Albatross
C) Kori Bustard
D) Eagle

✅ Answer: C) Kori Bustard
Explanation: The Kori Bustard is the heaviest flying bird (up to 18 kg).

• Ostrich is largest but flightless.

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Q39. Which of the following animals is viviparous?

A) Frog
B) Shark
C) Hen
D) Crocodile

✅ Answer: B) Shark
Explanation: Many sharks give birth to young (viviparous), unlike frogs, hens, and crocodiles (oviparous).

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Q40. Which is the longest bone in the human body?

A) Humerus
B) Tibia
C) Femur
D) Radius

✅ Answer: C) Femur
Explanation: Femur (thigh bone) is the longest and strongest bone in the human body.

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Q41. Which organ secretes bile?

A) Kidney
B) Liver
C) Pancreas
D) Stomach

✅ Answer: B) Liver
Explanation: The liver secretes bile, stored in gall bladder, helps in fat emulsification.

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Q42. The main excretory product of birds is:

A) Ammonia
B) Urea
C) Uric acid
D) Creatinine

✅ Answer: C) Uric acid
Explanation: Birds excrete uric acid (uricotelic), conserving water.

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Q43. Which part of the brain controls balance and posture?

A) Cerebrum
B) Cerebellum
C) Medulla
D) Hypothalamus

✅ Answer: B) Cerebellum
Explanation: The cerebellum coordinates voluntary movements, balance, and posture.

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Q44. Which animal has a single opening for both excretion and reproduction (cloaca)?

A) Human
B) Frog
C) Cat
D) Dog

✅ Answer: B) Frog
Explanation: Amphibians, reptiles, and birds have a cloaca, a common opening for excretion & reproduction.

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Q45. Which of the following is a cartilaginous fish?

A) Rohu
B) Catla
C) Shark
D) Salmon

✅ Answer: C) Shark
Explanation: Sharks belong to Chondrichthyes (cartilaginous fishes). Others are bony fishes.

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Q46. Which vitamin deficiency causes night blindness?

A) Vitamin A
B) Vitamin B1
C) Vitamin C
D) Vitamin D

✅ Answer: A) Vitamin A
Explanation: Deficiency of Vitamin A (retinol) causes night blindness (nyctalopia).

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Q47. Which of the following is a unicellular animal?

A) Hydra
B) Paramecium
C) Earthworm
D) Leech

✅ Answer: B) Paramecium
Explanation: Paramecium (Protozoa) is unicellular, unlike multicellular Hydra, earthworm, leech.

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Q48. Which hormone regulates blood sugar level?

A) Thyroxine
B) Insulin
C) Adrenaline
D) Growth hormone

✅ Answer: B) Insulin
Explanation: Insulin (pancreas) decreases blood sugar; glucagon increases it.

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Q49. Which blood vessel carries oxygenated blood from lungs to heart?

A) Pulmonary vein
B) Pulmonary artery
C) Aorta
D) Vena cava

✅ Answer: A) Pulmonary vein
Explanation: Pulmonary veins carry oxygenated blood from lungs to left atrium.

• Pulmonary artery → deoxygenated blood from heart to lungs.

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Q50. Which of the following is not a connective tissue?

A) Blood
B) Bone
C) Cartilage
D) Muscle

✅ Answer: D) Muscle
Explanation: Muscle is muscular tissue, not connective. Blood, bone, cartilage are connective.

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Zoology MCQs – Part 3 (Q51–Q75)

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Q51. The respiratory pigment in vertebrates is:

A) Hemocyanin
B) Hemoglobin
C) Myoglobin
D) Chlorocruorin

✅ Answer: B) Hemoglobin
Explanation: Vertebrates use hemoglobin (iron-containing pigment) in RBCs for oxygen transport.

• Hemocyanin → arthropods & mollusks.
• Myoglobin → oxygen storage in muscles.
• Chlorocruorin → some annelids.

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Q52. Which animal exhibits regeneration most effectively?

A) Earthworm
B) Hydra
C) Cockroach
D) Lizard

✅ Answer: B) Hydra
Explanation: Hydra can regenerate its entire body from a small fragment.

• Earthworm → partial regeneration.
• Cockroach → limited regeneration.
• Lizard → regenerates tail only.

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Q53. Which is the largest gland in the human body?

A) Pancreas
B) Liver
C) Thyroid
D) Salivary gland

✅ Answer: B) Liver
Explanation: The liver is the largest gland; it secretes bile, stores glycogen, detoxifies blood.

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Q54. Which blood cells are responsible for blood clotting?

A) RBCs
B) WBCs
C) Platelets
D) Plasma cells

✅ Answer: C) Platelets
Explanation: Platelets (thrombocytes) release clotting factors to stop bleeding.

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Q55. Which of the following is a mammal that can fly?

A) Bat
B) Pigeon
C) Ostrich
D) Eagle

✅ Answer: A) Bat
Explanation: Bats are flying mammals with membranous wings. Birds (pigeon, eagle, ostrich) are not mammals.

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Q56. Which part of the human brain controls hunger and thirst?

A) Cerebrum
B) Cerebellum
C) Hypothalamus
D) Medulla

✅ Answer: C) Hypothalamus
Explanation: The hypothalamus regulates hunger, thirst, temperature, and hormones.

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Q57. The excretory organ of cockroach is:

A) Nephridia
B) Flame cells
C) Kidneys
D) Malpighian tubules

✅ Answer: D) Malpighian tubules
Explanation: Insects excrete via Malpighian tubules.

• Nephridia → annelids.
• Flame cells → flatworms.
• Kidneys → vertebrates.

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Q58. Which of the following is a monotreme?

A) Kangaroo
B) Platypus
C) Dolphin
D) Tiger

✅ Answer: B) Platypus
Explanation: Platypus is a monotreme (egg-laying mammal). Kangaroo is marsupial; dolphin and tiger are placental mammals.

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Q59. The heart of a fish has how many chambers?

A) Two
B) Three
C) Four
D) Five

✅ Answer: A) Two
Explanation: Fish hearts have two chambers (1 atrium + 1 ventricle) for single circulation.

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Q60. Which of the following is called the “amphibian of the plant kingdom”?

A) Mosses
B) Ferns
C) Liverworts
D) Algae

✅ Answer: A) Mosses
Explanation: Mosses need water for fertilization like amphibians. (Though this is botany, it’s often linked in zoology MCQs as analogy).

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Q61. Which parasite causes malaria?

A) Trypanosoma
B) Giardia
C) Plasmodium
D) Leishmania

✅ Answer: C) Plasmodium
Explanation: Malaria is caused by Plasmodium (protozoan) transmitted by Anopheles mosquitoes.

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Q62. Which blood vessel carries deoxygenated blood from heart to lungs?

A) Pulmonary vein
B) Pulmonary artery
C) Aorta
D) Vena cava

✅ Answer: B) Pulmonary artery
Explanation: Pulmonary arteries carry deoxygenated blood from right ventricle to lungs.

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Q63. Which of the following is not a chordate feature?

A) Notochord
B) Dorsal nerve cord
C) Pharyngeal gill slits
D) Exoskeleton of chitin

✅ Answer: D) Exoskeleton of chitin
Explanation: Chitinous exoskeleton is a feature of arthropods, not chordates.

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Q64. Which animal has the ability of parthenogenesis?

A) Honey bee
B) Frog
C) Whale
D) Human

✅ Answer: A) Honey bee
Explanation: Male drones in honey bees arise from unfertilized eggs (parthenogenesis).

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Q65. Which organ helps in sound production in birds?

A) Larynx
B) Syrinx
C) Trachea
D) Bronchi

✅ Answer: B) Syrinx
Explanation: Birds produce sound using the syrinx, located at the base of the trachea.

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Q66. Which of the following animals undergo metamorphosis?

A) Earthworm
B) Cockroach
C) Frog
D) Lizard

✅ Answer: C) Frog
Explanation: Frogs undergo metamorphosis from tadpole (larval stage) to adult.

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Q67. Which animal shows canal system?

A) Hydra
B) Sycon
C) Starfish
D) Leech

✅ Answer: B) Sycon
Explanation: Sponges (Porifera like Sycon) have a canal system for circulation of water, respiration, and excretion.

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Q68. Which one is the smallest bone in the human body?

A) Stapes
B) Incus
C) Malleus
D) Fibula

✅ Answer: A) Stapes
Explanation: The stapes in the middle ear is the smallest bone in the human body.

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Q69. The process of shedding old skin in reptiles is called:

A) Molting
B) Regeneration
C) Ecdysis
D) Metamorphosis

✅ Answer: C) Ecdysis
Explanation: Reptiles shed skin by ecdysis (molting).

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Q70. Which of the following is a hermaphrodite animal?

A) Frog
B) Earthworm
C) Cockroach
D) Pigeon

✅ Answer: B) Earthworm
Explanation: Earthworms have both male and female reproductive organs (hermaphroditic).

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Q71. The scientific name of frog is:

A) Rana tigrina
B) Bufo bufo
C) Hyla arborea
D) Salamandra salamandra

✅ Answer: A) Rana tigrina
Explanation: The Indian bullfrog’s scientific name is Rana tigrina (now Hoplobatrachus tigerinus).

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Q72. Which of the following carries hereditary information?

A) Proteins
B) RNA & DNA
C) Lipids
D) Carbohydrates

✅ Answer: B) RNA & DNA
Explanation: DNA (main genetic material) and RNA (in some viruses) carry hereditary information.

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Q73. The mammalian middle ear contains how many bones?

A) One
B) Two
C) Three
D) Four

✅ Answer: C) Three
Explanation: Mammalian middle ear has three ossicles – malleus, incus, stapes.

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Q74. Which of the following is not a placental mammal?

A) Bat
B) Dolphin
C) Kangaroo
D) Human

✅ Answer: C) Kangaroo
Explanation: Kangaroo is a marsupial (pouched mammal), not placental.

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Q75. The largest phylum in Kingdom Animalia is:

A) Mollusca
B) Chordata
C) Arthropoda
D) Annelida

✅ Answer: C) Arthropoda
Explanation: Arthropoda (insects, crustaceans, spiders) is the largest phylum with ~80% of all known animals.

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Zoology MCQs – Part 4 (Q76–Q100)

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Q76. Which of the following animals has a 2-chambered heart?

A) Frog
B) Fish
C) Crocodile
D) Bird

✅ Answer: B) Fish
Explanation: Fishes have a 2-chambered heart (1 atrium + 1 ventricle) with single circulation.

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Q77. Which of the following animals exhibits bilateral symmetry?

A) Starfish (adult)
B) Hydra
C) Earthworm
D) Jellyfish

✅ Answer: C) Earthworm
Explanation: Earthworms show bilateral symmetry.

• Starfish → radial (adult).
• Hydra & Jellyfish → radial.

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Q78. Which of the following is an endothermic animal?

A) Crocodile
B) Pigeon
C) Lizard
D) Frog

✅ Answer: B) Pigeon
Explanation: Birds and mammals are endothermic (warm-blooded), maintaining constant body temperature.

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Q79. Which of the following is the first vertebrate group to show amniotic eggs?

A) Fishes
B) Amphibians
C) Reptiles
D) Mammals

✅ Answer: C) Reptiles
Explanation: Reptiles were the first to evolve amniotic eggs (with protective membranes).

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Q80. Which of the following animals has nephridia as excretory organ?

A) Earthworm
B) Cockroach
C) Hydra
D) Frog

✅ Answer: A) Earthworm
Explanation: Nephridia are excretory organs in annelids.

• Cockroach → Malpighian tubules.
• Hydra → diffusion.
• Frog → kidneys.

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Q81. Which of the following is the largest mammal?

A) Elephant
B) Blue whale
C) Giraffe
D) Rhino

✅ Answer: B) Blue whale
Explanation: The blue whale (Balaenoptera musculus) is the largest living mammal (up to 30 m long).

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Q82. Which of the following is not a reptile?

A) Turtle
B) Lizard
C) Salamander
D) Crocodile

✅ Answer: C) Salamander
Explanation: Salamanders belong to Amphibia, not reptiles.

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Q83. Which of the following structures is present only in mammals?

A) Lungs
B) Mammary glands
C) Heart
D) Kidneys

✅ Answer: B) Mammary glands
Explanation: Mammary glands are unique to mammals for feeding young.

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Q84. Which of the following is a sessile animal?

A) Hydra
B) Jellyfish
C) Starfish
D) Leech

✅ Answer: A) Hydra
Explanation: Hydra is sessile (attached to a surface), though it can show limited movement.

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Q85. Which of the following is the brain of the cell?

A) Mitochondria
B) Nucleus
C) Ribosome
D) Lysosome

✅ Answer: B) Nucleus
Explanation: The nucleus controls cellular functions, stores DNA, and regulates activities.

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Q86. Which animal is known as the shipworm (wood borer)?

A) Termite
B) Teredo
C) Silverfish
D) Ant

✅ Answer: B) Teredo
Explanation: Teredo (a mollusk) bores into wooden structures in water and is called “shipworm”.

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Q87. Which group of animals has book lungs?

A) Insects
B) Spiders
C) Fishes
D) Amphibians

✅ Answer: B) Spiders
Explanation: Spiders (Arachnida) possess book lungs for respiration.

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Q88. Which blood cells are called “soldiers of the body”?

A) RBCs
B) Platelets
C) WBCs
D) Plasma

✅ Answer: C) WBCs
Explanation: White Blood Cells protect the body against infections and foreign invaders.

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Q89. Which of the following is the “connecting link” between reptiles and birds?

A) Archaeopteryx
B) Ichthyostega
C) Seymouria
D) Peripatus

✅ Answer: A) Archaeopteryx
Explanation: Archaeopteryx is a fossil showing both reptilian and avian features (transitional form).

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Q90. Which of the following is the excretory organ in crustaceans?

A) Nephridia
B) Malpighian tubules
C) Green glands
D) Kidneys

✅ Answer: C) Green glands
Explanation: Crustaceans excrete via green glands (antennal glands).

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Q91. Which blood group is known as universal recipient?

A) O-
B) AB+
C) B+
D) A+

✅ Answer: B) AB+
Explanation: People with AB+ can receive blood from all groups.

• O- → universal donor.

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Q92. Which vitamin is synthesized in the skin on exposure to sunlight?

A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin D

✅ Answer: D) Vitamin D
Explanation: Vitamin D is synthesized in skin from cholesterol under UV rays.

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Q93. Which animal has a hydrostatic skeleton?

A) Earthworm
B) Snail
C) Cockroach
D) Spider

✅ Answer: A) Earthworm
Explanation: Earthworms use coelomic fluid as a hydrostatic skeleton for movement.

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Q94. Which is the fastest land animal?

A) Horse
B) Cheetah
C) Tiger
D) Lion

✅ Answer: B) Cheetah
Explanation: The cheetah is the fastest land animal (~100–120 km/h).

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Q95. The vertebral column in vertebrates develops from:

A) Ectoderm
B) Mesoderm
C) Endoderm
D) Notochord

✅ Answer: B) Mesoderm
Explanation: The vertebral column develops from mesodermal tissues (somites).

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Q96. The protein responsible for muscle contraction is:

A) Hemoglobin
B) Collagen
C) Actin & Myosin
D) Keratin

✅ Answer: C) Actin & Myosin
Explanation: Actin and myosin filaments slide to cause muscle contraction.

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Q97. Which blood vessels carry blood away from the heart?

A) Veins
B) Arteries
C) Capillaries
D) Venules

✅ Answer: B) Arteries
Explanation: Arteries carry blood away from the heart; veins carry blood towards it.

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Q98. Which is the largest land animal?

A) Blue whale
B) African elephant
C) Giraffe
D) Rhinoceros

✅ Answer: B) African elephant
Explanation: The African elephant is the largest land animal (~6 tons).

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Q99. Which organ in birds helps in grinding food?

A) Crop
B) Stomach
C) Gizzard
D) Intestine

✅ Answer: C) Gizzard
Explanation: Birds have a gizzard, a muscular organ that grinds food with help of pebbles.

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Q100. Which of the following is a cold-blooded vertebrate?

A) Whale
B) Penguin
C) Lizard
D) Bat

✅ Answer: C) Lizard
Explanation: Lizards are ectothermic (cold-blooded). Whales, penguins, and bats are warm-blooded.

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