Most Repeated MCQs

Solved Most Repeated MCQs with answers and explanations. Free practice questions for PPSC, FPSC, CSS and other government job exams on FreeSekho.

1. 1. Which planet lies at the farthest distance from the Sun in our solar system?

   1. Mercury
   2. Pluto
   3. Neptune ✓
   4. Uranus

2. 2. The Sun is classified as a _________.

   1. Star ✓
   2. Planet
   3. Meteor
   4. None

3. 3. Which of the following is NOT a conductor of electricity?

   1. Aluminium
   2. Gold
   3. Graphite
   4. All of these are conductors ✓

4. 4. At extremely low temperatures, which type of water freezes last?

   1. River water
   2. Canal water
   3. Sea water ✓
   4. Lake water

5. 5. Which planet can be seen most easily from Earth?

   1. Mercury
   2. Venus ✓
   3. Mars
   4. Jupiter

6. 6. What does the term dry ice refer to?

   1. Solid oxygen
   2. Solid carbon dioxide ✓
   3. Solid hydrogen
   4. Solid nitrogen

7. 7. Which of the following are rich sources of Vitamin B-complex?

   1. Green leafy vegetables
   2. Seeds ✓
   3. Fresh fruits and vegetables
   4. Sea foods

8. 8. Approximately how much of Earth’s surface is covered by water?

   1. 61%
   2. 51%
   3. 71% ✓
   4. 81%

9. 9. Which three elements are essential for the healthy growth of plants?

   1. Nitrogen, Phosphorus, Potassium ✓
   2. Nitrogen, Carbon, Phosphorus
   3. Nitrogen, Potassium
   4. Nitrogen, Sulphur, Phosphorus

10. 10. Which element is not abundantly found in the Earth’s crust?

    1. Silicon
    2. Radium ✓
    3. Aluminium
    4. Carbon

11. 11. Dr. Abdus Salam contributed to the unification of which fundamental forces?

    1. Electromagnetic and gravitational forces
    2. Electromagnetic and weak nuclear forces ✓
    3. Gravitational and weak nuclear forces
    4. Weak and strong nuclear forces

12. 12. Dry ice is best described as _________.

    1. Methane hydrate
    2. Liquid nitrogen
    3. Solid carbon dioxide ✓
    4. Frozen water

13. 13. Diamond, a costly ornament, is composed entirely of which element?

    1. Carbon ✓
    2. gold
    3. silver
    4. None

14. 14. What is the main cause of monsoon winds?

    1. Seasonal reversal of winds ✓
    2. Earth’s revolution
    3. Cloud movement
    4. Increase in temperature

15. 15. Fruits that develop without seeds, such as bananas, are called _________.

    1. Seedless fruits
    2. Parthenogenesis fruits
    3. Parthenocarpic fruits ✓
    4. Placental fruits

16. 16. Radar works on the same principle as sonar, but radar uses radio waves while sonar uses _________.

    1. Red waves
    2. Infrared waves
    3. Ultrasonic waves ✓
    4. Supersonic waves

17. 17. The magnifying power of a simple microscope can be increased by _________.

    1. Increasing the focal length of the lens
    2. Decreasing the focal length of the lens ✓
    3. Using a lens with large aperture
    4. Using a lens with small aperture

18. 18. What is the total volume of blood in a healthy adult human?

    1. 5–6 liters ✓
    2. 3–4 liters
    3. 8–10 liters
    4. 10–12 liters

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

    1. Thyroid
    2. Liver ✓
    3. Pancreas
    4. None

20. 20. Which disease among the following is caused by a virus?

    1. Smallpox ✓
    2. Tuberculosis
    3. Malaria
    4. Cholera

21. 21. Which part of a camera corresponds to the retina of the human eye?

    1. Lens
    2. Film ✓
    3. Aperture
    4. Shutter

22. 22. Television signals cannot cover very large distances mainly because _________.

    1. TV waves are weak
    2. Clear pictures cannot be transmitted beyond a certain distance
    3. The Earth is spherical ✓
    4. Air is a poor conductor of waves

23. 23. Water acts as an efficient coolant in car engines because it has _________.

    1. High thermal conductivity
    2. High specific heat capacity ✓
    3. High boiling point
    4. Strong cooling effect during evaporation

24. 24. Who first proposed the theory of the expanding universe?

    1. Einstein
    2. Newton
    3. Galileo
    4. Hubble ✓

25. 25. In which organisms is the haploid stage dominant in the life cycle?

    1. Mosses ✓
    2. Bacteria
    3. Protozoa
    4. None

26. 26. The Earth’s __________ is divided into about 15 major tectonic plates of different sizes.

    1. Mesosphere
    2. Stratosphere
    3. Lithosphere ✓
    4. None

27. 27. A Geiger–Muller counter is used for the detection of _________.

    1. Protons ✓
    2. Neutrons
    3. Photons
    4. None

28. 28. Which of the following is NOT a region of the spinal cord?

    1. Thoracic
    2. Pelvic ✓
    3. Lumbar
    4. None

29. 29. A tightrope walker carries a long pole mainly to _________.

    1. Support himself if he falls
    2. Spread his weight and reduce pressure on the rope
    3. Increase weight to tighten the rope
    4. Keep the center of gravity vertically above the rope ✓

30. 30. Protons and neutrons are located at the center of an atom called the _________.

    1. Nucleus ✓
    2. Headquarters
    3. Hub
    4. None

31. 31. How many vertebrae make up the vertebral column in humans?

    1. 5
    2. 10
    3. 12
    4. 33 ✓

32. 32. Which plant closes its lid when an insect lands on it?

    1. Sunflower
    2. Pitcher plant ✓
    3. Brassica plant
    4. None of these

33. 33. Short-sightedness (myopia) can be corrected using a _________.

    1. Concave lens ✓
    2. Convex lens
    3. Converging lens
    4. None of these

34. 34. Sunlight is an important natural source of _________.

    1. Vitamin C
    2. Vitamin D ✓
    3. Vitamin E
    4. Vitamin K

35. 35. The present evolutionary stage of the Sun is known as a _________.

    1. White dwarf
    2. Red giant
    3. Yellow dwarf ✓
    4. Orange dwarf

36. 36. Which hormone is secreted by the pancreas?

    1. Insulin ✓
    2. Vitamin A
    3. Bile juice
    4. None of these

37. 37. A star with zero volume and infinite density is known as a _________.

    1. White dwarf
    2. Blue giant
    3. Wolf-Rayet star
    4. Black hole ✓

38. 38. Which star appears brightest in the night sky?

    1. Betelgeuse
    2. Sirius ✓
    3. Rigel
    4. Polaris

39. 39. Which of the following is considered a pure substance?

    1. Sea water
    2. Brass
    3. Tap water
    4. Graphite ✓

40. 40. Which of the following is NOT an electromagnetic radiation?

    1. Red light
    2. Sound waves ✓
    3. X-rays
    4. Photon

41. 41. Kidney stones in humans are mainly composed of _________.

    1. Calcium oxalate ✓
    2. Sodium acetate
    3. Magnesium sulphate
    4. Calcium

42. 42. Afternoon rainfall in equatorial regions mainly occurs due to _________.

    1. Land breeze
    2. Monsoon
    3. Frontal activity
    4. Convection ✓

43. 43. A bore is caused by _________.

    1. Rising tides meeting river currents ✓
    2. Friction due to prevailing winds
    3. Strong winds during spring tides
    4. Unequal heating of oceans

44. 44. Which vitamin is destroyed when heated?

    1. Vitamin B
    2. Vitamin E
    3. Vitamin K
    4. Vitamin C ✓

45. 45. Which element is required for the conversion of solar energy into electrical energy?

    1. Ultra-pure carbon
    2. Silicon ✓
    3. Beryllium
    4. Tantalum

46. 46. Which substance is responsible for determining human skin color?

    1. Insulin
    2. Vitamin K
    3. Melanin ✓
    4. DNA

47. 47. The combined total of all ecosystems on Earth is known as the _________.

    1. Aerosphere
    2. Ionosphere
    3. Biosphere ✓
    4. Ozonosphere

48. 48. The combined total of all ecosystems on Earth is known as the _________.

    1. Aerosphere
    2. Ionosphere
    3. Biosphere ✓
    4. Ozonosphere

49. 49. The Big Bang event is believed to have occurred approximately _________.

    1. 10 billion years ago
    2. 15 billion years ago ✓
    3. 20 billion years ago
    4. 25 billion years ago

50. 50. What is the approximate height of the mesosphere layer of the atmosphere?

    1. 85 km ✓
    2. 50 km
    3. 40 km
    4. 10 km

51. 51. Damage to the alveoli due to smoking leads to which condition?

    1. Lung cancer
    2. Atherosclerosis
    3. Emphysema ✓
    4. Asthma

52. 52. The atmosphere near Earth’s surface is said to be “heated from below.” Which factor does NOT play a major role in this heating?

    1. Heat conduction upward from the warm surface
    2. Convection from the heated surface
    3. Absorption of infrared radiation emitted by the surface
    4. Heat coming from Earth’s interior ✓

53. 53. The boiling point of water mainly depends upon _________.

    1. Air temperature
    2. Relative humidity
    3. Atmospheric pressure ✓
    4. Air density

54. 54. The paper size known as “Elephant” measures 28 by _________.

    1. 23 inches ✓
    2. 25 inches
    3. 28 inches
    4. 31 inches

55. 55. Nearly what percentage of the Sun’s total energy is reflected back into space by Earth’s upper atmosphere?

    1. 10%
    2. 20%
    3. 30% ✓
    4. 50%

56. 56. Which planet is the largest in our solar system?

    1. Neptune
    2. Jupiter ✓
    3. Saturn
    4. Mars

57. 57. The scientific study of the formation of present and past landforms is called _________.

    1. Morphology
    2. Aerology
    3. Geomorphology ✓
    4. Biology

58. 58. Which planet appears brightest among the eight planets?

    1. Mercury
    2. Jupiter
    3. Venus ✓
    4. Neptune

59. 59. Who invented the electric battery?

    1. Nicolas Léonard Sadi Carnot
    2. Alessandro Volta ✓
    3. Michael Faraday
    4. Friedrich Bessel

60. 60. A microphone converts sound energy into _________.

    1. Microwaves
    2. Electrical signals ✓
    3. Optical signals
    4. Heat energy

61. 61. Stars are mainly composed of _________.

    1. Hot gases ✓
    2. Rocks
    3. Ice
    4. Light

62. 62. The approximate age of the Moon is _________.

    1. 4.51 billion years
    2. 4.55 billion years
    3. 4.53 billion years ✓
    4. 4.57 billion years

63. 63. Folate works together with which vitamin to form new red blood cells?

    1. Vitamin D
    2. Vitamin A
    3. Vitamin B₁₂ ✓
    4. None of the above

64. 64. Which type of mirror is commonly used in automobiles?

    1. Concave
    2. Convex ✓
    3. Plane
    4. Reflective

65. 65. The unit “bar” is used to measure _________.

    1. Temperature
    2. Heat
    3. Atmospheric pressure ✓
    4. Electric current

66. 66. Normal rainwater is slightly acidic mainly because _________.

    1. Dust particles are present in the air
    2. Carbon dioxide dissolves in water to form carbonic acid ✓
    3. Ozone depletion
    4. All of these

67. 67. The scientific study of insects is known as _________.

    1. Ichthyology
    2. Entomology ✓
    3. Zoology
    4. Botany

68. 68. What is the approximate surface temperature of the Sun?

    1. 5,778 Kelvin ✓
    2. 6,778 Kelvin
    3. 7,778 Kelvin
    4. 9,778 Kelvin

69. 69. The average distance between the Earth and the Sun is about ________

    1. 100 million km
    2. 150 million km ✓
    3. 200 million km
    4. 250 million km

70. 70. Inhaled air finally passes through which structure last?

    1. Bronchiole ✓
    2. Larynx
    3. Pharynx
    4. Trachea

71. 71. Winter solstice refers to the _________.

    1. Longest night ✓
    2. Longest day
    3. Shortest night
    4. Shortest day

72. 72. Who is regarded as the founder of the solar system model?

    1. Copernicus ✓
    2. Newton
    3. Galileo
    4. Kepler

73. 73. The scientific study of weather is called _________.

    1. Meteorology ✓
    2. Weatherology
    3. Ecology
    4. Geology

74. 74. Vitamin B is mainly found in _________.

    1. Sea foods
    2. Fruits and vegetables
    3. Seeds ✓
    4. None of these

75. 75. During a total solar eclipse, what is most likely to happen?

    1. Decrease in the rate of photosynthesis ✓
    2. Increase in the rate of photosynthesis
    3. Decrease in the rate of respiration
    4. No effect on either photosynthesis or respiration

76. 76. Which metal is the second most abundant in the Earth’s crust?

    1. Aluminium
    2. Calcium
    3. Silicon ✓
    4. Sodium

77. 77. In an electricity meter, the extreme right digit represents _________.

    1. One-fifth of a unit
    2. One-hundredth of a unit
    3. One-tenth of a unit ✓
    4. One-thousandth of a unit

78. 78. Saliva contains which digestive enzyme?

    1. Amylase ✓
    2. Bile
    3. Trypsin
    4. None of these

79. 79. Nail polish remover mainly contains _________.

    1. Acetone ✓
    2. Benzene
    3. Acetic acid
    4. Petroleum ether

80. 80. The Earth completes one rotation about its axis in _________.

    1. 23 hours 56 minutes 4 seconds ✓
    2. 24 hours
    3. 23 hours 57 minutes 9 seconds
    4. None of the above

81. 81. "Oil of vitriol” is the common name for _________.

    1. Nitric acid
    2. Hydrochloric acid
    3. Phosphoric acid
    4. Sulphuric acid ✓

82. 82. The science aimed at improving human genetic qualities is known as _________.

    1. Eugenics ✓
    2. Biotechnology
    3. Cloning
    4. Genealogy

83. 83. What is the normal range of human hearing in hertz?

    1. 10 Hz – 10 kHz
    2. 20 Hz – 20 kHz ✓
    3. 2000 Hz
    4. 40 Hz – 40 kHz

84. 84. Who was the first scientist to measure the speed of light?

    1. Einstein
    2. Newton
    3. Ole Roemer ✓
    4. Galileo

85. 85. The average kinetic energy of molecules determines the _________.

    1. Heat
    2. Temperature ✓
    3. Internal energy
    4. None

86. 86. The examination of a dead body to determine cause of death is called _________.

    1. Etymology
    2. Autopsy ✓
    3. Anatomy
    4. None of these

87. 87. The scientific study of soil is known as _________.

    1. Pedology ✓
    2. Pedagogy
    3. Sociology
    4. Demography

88. 88. Toxicity of which heavy metal can lead to liver cirrhosis?

    1. Copper ✓
    2. Lead
    3. Mercury
    4. Zinc

89. 89. P-waves are also referred to as _________.

    1. Push–pull waves ✓
    2. Side-to-side waves
    3. Up–down waves
    4. None of the above

90. 90. When was Pluto officially removed from the list of planets?

    1. September 24, 2006
    2. April 28, 2004
    3. January 26, 2006
    4. August 24, 2006 ✓

91. 91. Which three units form the basis of the metric system?

    1. Metre, litre, and gram ✓
    2. Centimetre, kilogram, and metric
    3. Kilogram, mass, and energy
    4. Kelvin, candela, and mole

92. 92. The olfactory nerves are associated with which sense?

    1. Smell ✓
    2. Touch
    3. Taste
    4. Hearing

93. 93. Which gas mixture is required for gas welding?

    1. Oxygen and ethylene
    2. Oxygen and hydrogen
    3. Acetylene and oxygen ✓
    4. Acetylene and hydrogen

94. 94. The Sun is approximately how many times larger than the Earth?

    1. 69 times
    2. 89 times
    3. 99 times
    4. 109 times ✓

95. 95. How many eyes does a worm possess?

    1. 1
    2. 2
    3. 3
    4. None ✓

96. 96. Approximately how many stripes are found on each side of a Grévy’s zebra?

    1. 20+
    2. 30+
    3. 80+ ✓
    4. 36+

97. 97. Mohs’ scale is used to measure the _________.

    1. Hardness of minerals ✓
    2. Viscosity of liquids
    3. Elasticity of materials
    4. Brittleness of substances

98. 98. Which of the following represents a chemical change?

    1. Sublimation of iodine ✓
    2. Heating a platinum wire
    3. Heating mercuric oxide powder
    4. Evaporation of alcohol

99. 99. Which vitamin does the liver use to produce new red blood cells?

    1. Vitamin B₁₂ ✓
    2. Vitamin B₆
    3. Vitamin A
    4. Vitamin K

100. 100. The rising of the “evening star” indicates the direction of the _________.

     1. South
     2. East
     3. West ✓
     4. North

101. 101. The scientific study that deals with heredity and variation is called _________.

     1. Cytology
     2. Genetics ✓
     3. Ecology
     4. Morphology

102. 102. Which type of blood cells help in blood clotting?

     1. Red blood cells
     2. White blood cells
     3. Platelets ✓
     4. Plasma

103. 103. Which gas is most abundant in Earth’s atmosphere?

     1. Oxygen
     2. Carbon dioxide
     3. Nitrogen ✓
     4. Argon

104. 104. The branch of biology that studies fungi is known as _________.

     1. Botany
     2. Zoology
     3. Mycology ✓
     4. Bacteriology

105. 105. Which organ in the human body filters blood and removes wastes?

     1. Liver
     2. Heart
     3. Kidney ✓
     4. Lungs

106. 106. What is the common name for sodium chloride?

     1. Washing soda
     2. Table salt ✓
     3. Baking soda
     4. Bleaching powder

107. 107. The force that opposes motion between two contacting surfaces is called _________.

     1. Gravity
     2. Friction ✓
     3. Friction
     4. Pressure

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

     1. Cerebrum
     2. Medulla
     3. Cerebellum ✓
     4. Hypothalamus

109. 109. Which element is essential for the formation of hemoglobin in blood?

     1. Calcium
     2. Iron ✓
     3. Sodium
     4. Potassium

110. 110. The energy obtained from the Sun is known as _________.

     1. Wind energy
     2. Thermal energy
     3. Solar energy ✓
     4. Hydro energy

111. 111. The study of diseases and their causes is called _________.

     1. Pathology ✓
     2. Physiology
     3. Anatomy
     4. Psychology

112. 112. Which vitamin helps in the clotting of blood?

     1. Vitamin A
     2. Vitamin B
     3. Vitamin C
     4. Vitamin K ✓

113. 113. Which organ produces bile juice?

     1. Pancreas
     2. Gall bladder
     3. Liver ✓
     4. Stomach

114. 114. What type of energy is stored in food?

     1. Mechanical energy
     2. Chemical energy ✓
     3. Electrical energy
     4. Heat energy

115. 115. The outermost layer of the Earth is called the _________.

     1. Mantle
     2. Core
     3. Crust ✓
     4. Lithosphere

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

     1. A
     2. B
     3. AB
     4. O ✓

117. 117. The unit used to measure electric current is _________.

     1. Volt
     2. Ohm
     3. Ampere ✓
     4. Watt

118. 118. The gas essential for respiration in humans is _________.

     1. Carbon dioxide
     2. Nitrogen
     3. Oxygen ✓
     4. Hydrogen

119. 119. Which sense organ is responsible for hearing?

     1. Eye
     2. Nose
     3. Ear ✓
     4. Skin

120. 120. The process by which green plants prepare their food is called _________.

     1. Respiration
     2. Transpiration
     3. Photosynthesis ✓
     4. Germination

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

     1. 90°C
     2. 95°C
     3. 100°C ✓
     4. 110°C

122. 122. Which planet is known as the Red Planet?

     1. Venus
     2. Mars ✓
     3. Jupiter
     4. Saturn

123. 123. The device used to measure atmospheric pressure is called a _________.

     1. Thermometer
     2. Barometer ✓
     3. Hygrometer
     4. Anemometer

124. 124. Which metal is liquid at room temperature?

     1. Iron
     2. Aluminium
     3. Mercury ✓
     4. Copper

125. 125. Sound cannot travel through _________.

     1. Air
     2. Water
     3. Solids
     4. Vacuum ✓

126. 126. Which part of the cell controls all its activities?

     1. Cytoplasm
     2. Cell wall
     3. Nucleus ✓
     4. Mitochondria

127. 127. The movement of water across a semi-permeable membrane is known as _________.

     1. Diffusion
     2. Osmosis ✓
     3. Transpiration
     4. Absorption

128. 128. Which organelle is referred to as the powerhouse of the cell?

     1. Ribosome
     2. Chloroplast
     3. Mitochondria ✓
     4. Golgi body

129. 129. The change of a liquid into vapor is called _________.

     1. Condensation
     2. Freezing
     3. Evaporation ✓
     4. Melting

130. 130. Which force pulls objects toward the center of the Earth?

     1. Magnetism
     2. Friction
     3. Gravity ✓
     4. Pressure

131. 131. Which planet has the largest number of moons?

     1. Earth
     2. Mars
     3. Jupiter ✓
     4. Venus

132. 132. Which type of teeth are used for cutting food?

     1. Canines
     2. Premolars
     3. Molars
     4. Incisors ✓

133. 133. The study of the human body’s structure is called _________.

     1. Physiology
     2. Anatomy ✓
     3. Biology
     4. Pathology

134. 134. Which gas is released during photosynthesis?

     1. Carbon dioxide
     2. Oxygen ✓
     3. Nitrogen
     4. Hydrogen

135. 135. Which vitamin deficiency causes rickets?

     1. Vitamin A
     2. Vitamin B
     3. Vitamin C
     4. Vitamin D ✓

136. 136. The smallest unit of matter that retains chemical properties is the _________.

     1. Cell
     2. Molecule
     3. Atom ✓
     4. Compound

137. 137. Which instrument is used to measure temperature?

     1. Barometer
     2. Hygrometer
     3. Thermometer ✓
     4. Anemometer

138. 138. Which form of energy is possessed by a moving object?

     1. Potential energy
     2. Chemical energy
     3. Kinetic energy ✓
     4. Nuclear energy

139. 139. The layer of the atmosphere that contains the ozone layer is the _________.

     1. Troposphere
     2. Mesosphere
     3. Stratosphere ✓
     4. Thermosphere

140. 140. Which planet is closest to the Sun?

     1. Venus
     2. Earth
     3. Mercury ✓
     4. Mars

141. 141. Which blood cells are responsible for fighting infections?

     1. Red blood cells
     2. Platelets
     3. White blood cells ✓
     4. Plasma

142. 142. Which simple machine is represented by a seesaw?

     1. Pulley
     2. Lever ✓
     3. Wheel and axle
     4. Inclined plane

143. 143. The process of breathing in is known as _________.

     1. Exhalation
     2. Respiration
     3. Inhalation ✓
     4. Diffusion

144. 144. Which metal is commonly used for electrical wiring?

     1. Iron
     2. Aluminium
     3. Copper ✓
     4. Zinc

145. 145. The green pigment present in plants is called _________.

     1. Carotene
     2. Xanthophyll
     3. Chlorophyll ✓
     4. Anthocyanin

146. 146. Which organ in the human body pumps blood?

     1. Brain
     2. Lungs
     3. Heart ✓
     4. Kidney

147. 147. What is the SI unit of force?

     1. Joule
     2. Newton ✓
     3. Pascal
     4. Watt

148. 148. Which part of the plant conducts water and minerals?

     1. Phloem
     2. Cortex
     3. Xylem ✓
     4. Cambium

149. 149. The study of stars and planets is called _________.

     1. Astrology
     2. Astronomy ✓
     3. Geography
     4. Cosmology

150. 150. Which type of reproduction involves only one parent?

     1. Sexual reproduction
     2. Asexual reproduction ✓
     3. Vegetative reproduction
     4. Binary fission

151. 151. Which gas is produced when acids react with metals?

     1. Oxygen
     2. Nitrogen
     3. Hydrogen ✓
     4. Carbon dioxide

152. 152. The main function of red blood cells is to _________.

     1. Fight infections
     2. Help in clotting
     3. Transport oxygen ✓
     4. Produce hormones

153. 153. Which organ in plants carries prepared food to different parts?

     1. Xylem
     2. Cortex
     3. Cambium
     4. Phloem ✓

154. 154. Which planet is known for its prominent ring system?

     1. Jupiter
     2. Saturn ✓
     3. Uranus
     4. Neptune

155. 155. The process by which water changes into ice is called _________.

     1. Evaporation
     2. Condensation
     3. Freezing ✓
     4. Sublimation

156. 156. Which metal is the best conductor of electricity?

     1. Copper
     2. Aluminium
     3. Silver ✓
     4. Gold

157. 157. Which part of the human eye controls the amount of light entering it?

     1. Retina
     2. Iris ✓
     3. Cornea
     4. Lens

158. 158. Which type of joint allows movement in all directions?

     1. Hinge joint
     2. Pivot joint
     3. Ball-and-socket joint ✓
     4. Fixed joint

159. 159. Which gas is released during respiration?

     1. Oxygen
     2. Nitrogen
     3. Carbon dioxide ✓
     4. Hydrogen

160. 160. Which planet is referred to as Earth’s twin due to similar size?

     1. Mars
     2. Venus ✓
     3. Mercury
     4. Neptune

161. 161. The unit used to measure force is _________.

     1. Joule
     2. Watt
     3. Newton ✓
     4. Pascal

162. 162. Which sense organ detects taste?

     1. Eye
     2. Nose
     3. Tongue ✓
     4. Skin

163. 163. Which layer of the atmosphere is closest to the Earth’s surface?

     1. Stratosphere
     2. Mesosphere
     3. Troposphere ✓
     4. Thermosphere

164. 164. Which substance speeds up a chemical reaction without being consumed?

     1. Reactant
     2. Catalyst ✓
     3. Solvent
     4. Inhibitor

165. 165. The process of breaking down food into simpler substances is called _________.

     1. Respiration
     2. Digestion ✓
     3. Absorption
     4. Assimilation

166. 166. Which metal is used in making aircraft due to its light weight?

     1. Copper
     2. Iron
     3. Aluminium ✓
     4. Zinc

167. 167. Which vitamin helps maintain healthy eyesight?

     1. Vitamin A ✓
     2. Vitamin B
     3. Vitamin C
     4. Vitamin D

168. 168. Which organ removes carbon dioxide from the blood?

     1. Heart
     2. Liver
     3. Lungs ✓
     4. Kidneys

169. 169. The change of solid directly into gas is known as _________.

     1. Evaporation
     2. Condensation
     3. Sublimation ✓
     4. Melting

170. 170. Which type of blood vessel carries blood away from the heart?

     1. Veins
     2. Capillaries
     3. Arteries ✓
     4. Venules

171. 171. Which device is used to measure electric current?

     1. Voltmeter
     2. Ammeter ✓
     3. Galvanometer
     4. Ohmmeter

172. 172. Which planet has the shortest year?

     1. Earth
     2. Mars
     3. Mercury ✓
     4. Venus

173. 173. Which gas is essential for combustion?

     1. Nitrogen
     2. Hydrogen
     3. Oxygen ✓
     4. Carbon dioxide

174. 174. Which organ in the human body produces urine?

     1. Liver
     2. Lungs
     3. Kidneys ✓
     4. Stomach

175. 175. Which branch of science deals with the study of matter and energy?

     1. Biology
     2. Chemistry
     3. Physics ✓
     4. Geology

176. 176. Which gas is used by plants during the process of photosynthesis?

     1. Oxygen
     2. Nitrogen
     3. Carbon dioxide ✓
     4. Hydrogen

177. 177. Which vitamin helps the body absorb calcium effectively?

     1. Vitamin A
     2. Vitamin B
     3. Vitamin C
     4. Vitamin D ✓

178. 178. The instrument used to observe distant celestial objects is called a _________.

     1. Microscope
     2. Telescope ✓
     3. Periscope
     4. Spectroscope

179. 179. Which part of the digestive system absorbs most of the nutrients?

     1. Stomach
     2. Large intestine
     3. Small intestine ✓
     4. Esophagus

180. 180. Which planet is famous for having a prominent red spot?

     1. Mars
     2. Saturn
     3. Jupiter ✓
     4. Uranus

181. 181. The SI unit of work is _________.

     1. Watt
     2. Joule ✓
     3. Newton
     4. Pascal

182. 182. Which metal is liquid at room temperature?

     1. Sodium
     2. Mercury ✓
     3. Aluminium
     4. Iron

183. 183. Which type of energy is stored in a stretched rubber band?

     1. Kinetic energy
     2. Heat energy
     3. Potential energy ✓
     4. Electrical energy

184. 184. Which organ in the human body is mainly responsible for thinking?

     1. Heart
     2. Brain ✓
     3. Lungs
     4. Liver

185. 185. Which planet takes the longest time to complete one revolution around the Sun?

     1. Jupiter
     2. Saturn
     3. Uranus
     4. Neptune ✓

186. 186. Which part of the human ear helps maintain balance?

     1. Cochlea
     2. Eardrum
     3. Semicircular canals ✓
     4. Auditory nerve

187. 187. Which gas is released when fuels burn completely?

     1. Carbon monoxide
     2. Oxygen
     3. Nitrogen
     4. Carbon dioxide ✓

188. 188. Which type of rock is formed from molten magma?

     1. Sedimentary
     2. Metamorphic
     3. Igneous ✓
     4. Fossil

189. 189. The transfer of heat through direct contact is called _________.

     1. Radiation
     2. Convection
     3. Conduction ✓
     4. Insulation

190. 190. Which sense organ helps humans detect smell?

     1. Ear
     2. Eye
     3. Nose ✓
     4. Tongue

191. 191. Which device is used to measure humidity in air?

     1. Barometer
     2. Thermometer
     3. Hygrometer ✓
     4. Anemometer

192. 192. Which planet has the greatest number of rings?

     1. Jupiter
     2. Saturn ✓
     3. Uranus
     4. Neptune

193. 193. Which organ in plants is responsible for photosynthesis?

     1. Root
     2. Stem
     3. Leaf ✓
     4. Flower

194. 194. The speed of light in vacuum is approximately _________.

     1. 3 × 10⁸ m/s ✓
     2. 3 × 10⁶ m/s
     3. 3 × 10⁵ m/s
     4. 3 × 10³ m/s

195. 195. Which blood group is known as the universal recipient?

     1. A
     2. B
     3. AB ✓
     4. O

196. 196. Which layer of the atmosphere burns most meteors before they reach Earth?

     1. Troposphere
     2. Stratosphere
     3. Mesosphere ✓
     4. Thermosphere

197. 197. Which organ controls voluntary actions in the human body?

     1. Cerebellum
     2. Medulla
     3. Cerebrum ✓
     4. Hypothalamus

198. 198. Which process involves the release of energy from food?

     1. Photosynthesis
     2. Respiration ✓
     3. Digestion
     4. Transpiration

199. 199. Which metal is used in thermometers?

     1. Alcohol
     2. Mercury ✓
     3. Water
     4. Oil

200. 200. Which branch of science deals with the study of Earth and its features?

     1. Biology
     2. Physics
     3. Chemistry
     4. Geography ✓