Natural Science MCQs

Questions and Answers (31–60)

31. What is the smallest unit of matter?

Answer: Atom

32. Which organ controls the human body?

Answer: Brain

33. What is the SI unit of electric current?

Answer: Ampere

34. Which blood cells carry oxygen?

Answer: Red blood cells

35. What is the natural satellite of Earth?

Answer: Moon

36. What is the process of water cycle where water vapor turns into liquid?

Answer: Condensation

37. Which gas is most abundant in Earth's atmosphere?

Answer: Nitrogen

38. What is the SI unit of pressure?

Answer: Pascal

39. Which organ helps in digestion by producing enzymes?

Answer: Pancreas

40. What is the basic structural unit of the nervous system?

Answer: Neuron

41. Which metal is the best conductor of electricity?

Answer: Silver

42. What is the pH value of pure water?

Answer: 7

43. Which layer protects Earth from harmful ultraviolet rays?

Answer: Ozone layer

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

Answer: Iris

45. What is the study of living organisms called?

Answer: Biology

46. What is the SI unit of frequency?

Answer: Hertz

47. Which organ filters blood in the human body?

Answer: Kidneys

48. Which process converts sugar into energy in cells?

Answer: Cellular respiration

49. Which gas is produced during photosynthesis?

Answer: Oxygen

50. What is the largest bone in the human body?

Answer: Femur

51. Which scientist proposed the theory of relativity?

Answer: Albert Einstein

52. What is the unit of electrical resistance?

Answer: Ohm

53. Which planet is known as the Morning Star?

Answer: Venus

54. What is the main gas responsible for global warming?

Answer: Carbon dioxide

55. What is the largest ocean on Earth?

Answer: Pacific Ocean

56. Which blood group is known as universal donor?

Answer: O negative

57. Which part of the plant absorbs water from soil?

Answer: Roots

58. What is the SI unit of work?

Answer: Joule

59. What type of energy is stored in a stretched spring?

Answer: Elastic potential energy

60. What is the study of the Earth called?

Answer: Geology