Science Quiz – 100 Questions

✅ Science Quiz – 100 Questions

1. What is the chemical symbol for water?

A) HO

B) H2O ✔

C) OH

D) O2

2. Which planet is known as the Red Planet?

A) Venus

B) Jupiter

C) Mars ✔

D) Saturn

3. What is the main gas found in the air we breathe?

A) Carbon dioxide

B) Oxygen

C) Nitrogen ✔

D) Hydrogen

4. Which part of the cell contains the genetic material?

A) Ribosome

B) Nucleus ✔

C) Cytoplasm

D) Cell wall

5. What force keeps us on the ground?

A) Magnetism

B) Gravity ✔

C) Friction

D) Electricity

6. Which organ pumps blood throughout the body?

A) Brain

B) Kidney

C) Heart ✔

D) Liver

7. What is the boiling point of water at sea level?

A) 90°C

B) 100°C ✔

C) 110°C

D) 120°C

8. What type of energy is stored in food?

A) Kinetic energy

B) Thermal energy

C) Chemical energy ✔

D) Nuclear energy

9. Which vitamin is produced when the skin is exposed to sunlight?

A) Vitamin A

B) Vitamin B12

C) Vitamin C

D) Vitamin D ✔

10. Which is the largest organ in the human body?

A) Heart

B) Brain

C) Liver

D) Skin ✔

11. What is the freezing point of water?

A) 0°C ✔

B) 10°C

C) -5°C

D) 100°C

12. What is the center of an atom called?

A) Proton

B) Nucleus ✔

C) Electron

D) Neutron

13. Which part of the eye controls the amount of light entering?

A) Retina

B) Cornea

C) Iris ✔

D) Lens

14. Which gas do plants take in for photosynthesis?

A) Oxygen

B) Nitrogen

C) Carbon dioxide ✔

D) Hydrogen

15. What is the unit of electric current?

A) Volt

B) Ampere ✔

C) Ohm

D) Watt

16. Which metal is liquid at room temperature?

A) Iron

B) Mercury ✔

C) Copper

D) Aluminum

17. What is the basic unit of life?

A) Molecule

B) Atom

C) Cell ✔

D) Tissue

18. Which part of the brain controls balance and coordination?

A) Cerebrum

B) Brain stem

C) Cerebellum ✔

D) Hypothalamus

19. What type of tissue connects muscles to bones?

A) Ligaments

B) Cartilage

C) Tendons ✔

D) Nerves

20. What is the most abundant element in the universe?

A) Oxygen

B) Hydrogen ✔

C) Carbon

D) Nitrogen

21. What is the pH value of pure water?

A) 5

B) 7 ✔

C) 9

D) 11

22. Which blood group is known as the universal donor?

A) AB

B) B

C) O ✔

D) A

23. What is the powerhouse of the cell?

A) Nucleus

B) Ribosome

C) Mitochondria ✔

D) Golgi body

24. Which planet has the most rings?

A) Earth

B) Jupiter

C) Saturn ✔

D) Uranus

25. Which is the smallest bone in the human body?

A) Femur

B) Stapes ✔

C) Tibia

D) Humerus

26. What phenomenon causes a rainbow?

A) Reflection

B) Refraction and dispersion ✔

C) Diffraction

D) Polarization

27. What is the primary source of energy for the Earth?

A) Moon

B) Wind

C) Sun ✔

D) Geothermal energy

28. What do enzymes do in the body?

A) Store energy

B) Act as hormones

C) Speed up chemical reactions ✔

D) Carry oxygen

29. Which particle has no electrical charge?

A) Proton

B) Electron

C) Neutron ✔

D) Positron

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

A) Veins

B) Arteries ✔

C) Capillaries

D) Lymph nodes

31. Which gas is responsible for global warming?

A) Nitrogen

B) Oxygen

C) Carbon dioxide ✔

D) Helium

32. What is the chemical formula for table salt?

A) NaCl ✔

B) KCl

C) CaCl

D) HCl

33. What process do plants use to make their own food?

A) Respiration

B) Photosynthesis ✔

C) Fermentation

D) Decomposition

34. Which organ helps in digestion by producing bile?

A) Stomach

B) Pancreas

C) Liver ✔

D) Small intestine

35. What type of wave is sound?

A) Electromagnetic

B) Mechanical ✔

C) Light

D) Gravitational

36. What is the main function of red blood cells?

A) Fight infections

B) Carry oxygen ✔

C) Produce hormones

D) Store fat

37. Which law states that energy cannot be created or destroyed?

A) Newton’s law

B) Law of conservation of energy ✔

C) Boyle’s law

D) Ohm’s law

38. What vitamin helps in blood clotting?

A) Vitamin A

B) Vitamin K ✔

C) Vitamin E

D) Vitamin D

39. Which organ removes waste from the blood?

A) Liver

B) Kidney ✔

C) Pancreas

D) Lung

40. What is the chemical symbol for gold?

A) Ag

B) Au ✔

C) Gd

D) Ga

41. Which process converts solid directly into gas?

A) Melting

B) Freezing

C) Sublimation ✔

D) Condensation

42. Which is the hardest natural substance on Earth?

A) Iron

B) Quartz

C) Diamond ✔

D) Graphite

43. What is the function of white blood cells?

A) Carry oxygen

B) Produce hormones

C) Fight infection ✔

D) Help in digestion

44. Which planet is the largest in the Solar System?

A) Mars

B) Saturn

C) Jupiter ✔

D) Neptune

45. What is the process by which water moves from roots to leaves?

A) Respiration

B) Transpiration ✔

C) Fermentation

D) Photosynthesis

46. What causes tides on Earth?

A) Solar winds

B) Earth’s rotation

C) Gravitational pull of the moon ✔

D) Ocean currents

47. Which organ stores and concentrates bile?

A) Liver

B) Gallbladder ✔

C) Pancreas

D) Intestine

48. What is the main component of natural gas?

A) Ethane

B) Methane ✔

C) Propane

D) Butane

49. Which vitamin is water-soluble?

A) Vitamin A

B) Vitamin D

C) Vitamin B ✔

D) Vitamin E

50. Which planet is closest to the Sun?

A) Earth

B) Mercury ✔

C) Venus

D) Mars

51. What is the chemical formula for oxygen gas?

A) O

B) O2 ✔

C) O3

D) OH

52. What is the human body’s largest bone?

A) Femur ✔

B) Skull

C) Spine

D) Humerus

53. What causes muscles to contract?

A) Electrical signals from the brain ✔

B) Hormones

C) Blood pressure

D) Water loss

54. What is the function of chlorophyll?

A) Store energy

B) Absorb sunlight for photosynthesis ✔

C) Protect leaves

D) Help in respiration

55. Which element is essential for forming thyroid hormones?

A) Iron

B) Iodine ✔

C) Calcium

D) Zinc

56. Which part of the brain regulates heartbeat and breathing?

A) Cerebellum

B) Cerebrum

C) Brain stem ✔

D) Hypothalamus

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

A) Thyroid

B) Liver ✔

C) Adrenal

D) Pancreas

58. What is the main component of the Earth's atmosphere after nitrogen?

A) Oxygen ✔

B) Carbon dioxide

C) Argon

D) Water vapor

59. What is the process by which green plants release water vapor?

A) Photosynthesis

B) Respiration

C) Transpiration ✔

D) Diffusion

60. Which is an example of a conductor of electricity?

A) Rubber

B) Glass

C) Copper ✔

D) Plastic

61. What causes corrosion of iron?

A) Salt

B) Water and oxygen ✔

C) Heat

D) Pressure

62. What is the main function of platelets?

A) Carry oxygen

B) Fight disease

C) Help in blood clotting ✔

D) Store nutrients

63. Which part of the eye is responsible for focusing?

A) Retina

B) Lens ✔

C) Iris

D) Cornea

64. Which gas is used in balloons to make them float?

A) Oxygen

B) Hydrogen

C) Helium ✔

D) Carbon dioxide

65. What is the main source of protein in the human diet?

A) Vegetables

B) Fruits

C) Meat, fish, and legumes ✔

D) Grains

66. What is the chemical symbol for iron?

A) Ir

B) Fe ✔

C) I

D) Fr

67. Which is the smallest unit of an element?

A) Molecule

B) Cell

C) Atom ✔

D) Organ

68. Which part of the plant absorbs water and minerals from the soil?

A) Stem

B) Leaf

C) Flower

D) Root ✔

69. What is the name of the process where liquid changes into vapor?

A) Condensation

B) Evaporation ✔

C) Freezing

D) Melting

70. Which is the primary source of Vitamin C?

A) Milk

B) Oranges and lemons ✔

C) Meat

D) Fish

71. Which layer of the Earth is liquid?

A) Crust

B) Mantle

C) Outer core ✔

D) Inner core

72. What is the function of the lungs?

A) Produce blood

B) Store food

C) Exchange oxygen and carbon dioxide ✔

D) Filter toxins

73. Which blood cells fight infections?

A) Red blood cells

B) Platelets

C) White blood cells ✔

D) Plasma

74. What is the main gas responsible for the process of respiration?

A) Oxygen ✔

B) Carbon dioxide

C) Nitrogen

D) Hydrogen

75. What is the SI unit of force?

A) Joule

B) Newton ✔

C) Watt

D) Pascal

76. Which is the process where plants release oxygen?

A) Transpiration

B) Photosynthesis ✔

C) Respiration

D) Fermentation

77. What is the primary mineral in bones?

A) Sodium

B) Calcium ✔

C) Potassium

D) Magnesium

78. Which vitamin helps in wound healing?

A) Vitamin A

B) Vitamin B

C) Vitamin C ✔

D) Vitamin D

79. Which organ is responsible for filtering blood?

A) Stomach

B) Kidney ✔

C) Heart

D) Lung

80. Which is the hardest tissue in the human body?

A) Cartilage

B) Bone

C) Enamel ✔

D) Skin

81. What is the main cause of acid rain?

A) Carbon dioxide

B) Nitrogen and sulfur oxides ✔

C) Water vapor

D) Methane

82. What is the main function of the liver?

A) Pump blood

B) Produce insulin

C) Detoxify chemicals and metabolize drugs ✔

D) Store oxygen

83. What is the unit of energy?

A) Newton

B) Watt

C) Joule ✔

D) Tesla

84. Which force opposes motion between two surfaces?

A) Gravity

B) Friction ✔

C) Magnetism

D) Pressure

85. What is the process by which plants absorb sunlight?

A) Respiration

B) Photosynthesis ✔

C) Fermentation

D) Evaporation

86. Which vitamin is necessary for strong bones and teeth?

A) Vitamin A

B) Vitamin B

C) Vitamin C

D) Vitamin D ✔

87. What is the main element in organic compounds?

A) Nitrogen

B) Carbon ✔

C) Hydrogen

D) Oxygen

88. Which organ produces insulin?

A) Liver

B) Pancreas ✔

C) Kidney

D) Heart

89. Which is the nearest star to Earth?

A) Sirius

B) Alpha Centauri

C) Sun ✔

D) Betelgeuse

90. Which process allows water to move up through plants?

A) Capillary action ✔

B) Osmosis

C) Diffusion

D) Respiration

91. What is the chemical symbol for carbon dioxide?

A) CO ✔

B) CO2 ✔

C) C2O

D) O2C

92. Which gas is necessary for combustion?

A) Carbon dioxide

B) Oxygen ✔

C) Nitrogen

D) Helium

93. Which organ helps in the production of bile?

A) Gallbladder

B) Liver ✔

C) Pancreas

D) Stomach

94. Which is an example of a renewable energy source?

A) Coal

B) Oil

C) Solar ✔

D) Natural gas

95. What type of bond holds atoms together in a molecule?

A) Ionic

B) Covalent ✔

C) Metallic

D) Hydrogen

96. What is the chemical symbol for nitrogen?

A) Ni

B) N ✔

C) Nt

D) Na

97. What is the main purpose of the respiratory system?

A) To produce blood

B) To exchange gases ✔

C) To digest food

D) To store minerals

98. Which part of the plant is responsible for reproduction?

A) Leaf

B) Stem

C) Root

D) Flower ✔

99. What is the role of insulin in the body?

A) Regulate blood pressure

B) Store fats

C) Regulate blood sugar ✔

D) Fight infections

100. Which layer of the atmosphere protects Earth from harmful UV rays?

A) Troposphere

B) Stratosphere ✔

C) Mesosphere

D) Thermosphere

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