Why Do We Fall Ill Part 3: MCQs (Q51–Q75)
🩺 Why Do We Fall Ill – Class 9 Science MCQs
Section 3: Principles of Treatment & Prevention, Immunity & Vaccination (Q51–Q75)
Q51. Which of these is NOT a principle of treatment of infectious diseases?
A. Reducing symptoms
B. Killing microbes
C. Improving immunity
D. Preventing air pollution
✅ Correct Answer: D. Preventing air pollution
Explanation:
- Treatment focuses on reducing effects (fever, pain), eliminating microbes, and boosting immunity — not air pollution.
Q52. Symptom-reducing drugs are called:
A. Antibiotics
B. Analgesics
C. Antivirals
D. Vaccines
✅ Correct Answer: B. Analgesics
Explanation:
- Analgesics reduce pain and fever, antibiotics kill bacteria, antivirals fight viruses, vaccines prevent.
Q53. Antibiotics are effective against:
A. Bacteria
B. Viruses
C. Protozoa
D. Fungi
✅ Correct Answer: A. Bacteria
Explanation:
- Antibiotics act on bacterial cell wall/metabolism → ineffective on viruses.
Q54. Which of the following diseases cannot be treated with antibiotics?
A. Cholera
B. Tuberculosis
C. Dengue
D. Typhoid
✅ Correct Answer: C. Dengue
Explanation:
- Dengue is viral; antibiotics kill only bacteria.
Q55. Antiviral medicines are difficult to make because:
A. Viruses are large
B. Viruses use host machinery
C. Viruses are plants
D. Viruses don’t cause disease
✅ Correct Answer: B. Viruses use host machinery
Explanation:
- Hard to target virus without damaging host cell.
Q56. Which of the following is NOT a principle of prevention?
A. General health measures
B. Specific protection
C. Isolation
D. Killing patient
✅ Correct Answer: D. Killing patient
Q57. Prevention of diseases is better than cure because:
A. Treatment is costly
B. Diseases cause suffering
C. Prevention avoids transmission
D. All of these
✅ Correct Answer: D. All of these
Q58. Vaccines work by providing:
A. Ready-made antibodies
B. Memory cells and immunity
C. Analgesic effect
D. Antibiotic resistance
✅ Correct Answer: B. Memory cells and immunity
Q59. Immunity due to vaccine is called:
A. Active acquired immunity
B. Passive acquired immunity
C. Innate immunity
D. Genetic immunity
✅ Correct Answer: A. Active acquired immunity
Q60. Injecting pre-formed antibodies into the body provides:
A. Active immunity
B. Passive immunity
C. No immunity
D. Vaccination
✅ Correct Answer: B. Passive immunity
Q61. Example of passive immunity:
A. Vaccination
B. Breast milk antibodies
C. Polio drops
D. TB vaccine
✅ Correct Answer: B. Breast milk antibodies
Q62. Which of these is a general method of prevention?
A. Balanced diet
B. Public hygiene
C. Clean drinking water
D. All of these
✅ Correct Answer: D. All of these
Q63. Which of the following is a specific method of prevention?
A. Vaccination
B. Antibiotics
C. Analgesics
D. Isolation
✅ Correct Answer: A. Vaccination
Q64. Polio vaccine was developed by:
A. Louis Pasteur
B. Jonas Salk
C. Alexander Fleming
D. Robert Koch
✅ Correct Answer: B. Jonas Salk
Q65. Which of these diseases can be prevented by vaccination?
A. Polio
B. TB
C. Hepatitis B
D. All of these
✅ Correct Answer: D. All of these
Q66. The vaccine for smallpox was developed by:
A. Edward Jenner
B. Alexander Fleming
C. Louis Pasteur
D. Robert Koch
✅ Correct Answer: A. Edward Jenner
Q67. Which of the following is NOT a vaccine-preventable disease?
A. Cholera
B. Diabetes
C. Polio
D. Tuberculosis
✅ Correct Answer: B. Diabetes
Q68. BCG vaccine is given against:
A. Polio
B. Tuberculosis
C. Cholera
D. Tetanus
✅ Correct Answer: B. Tuberculosis
Q69. DPT vaccine protects against:
A. Diphtheria, Polio, Typhoid
B. Diphtheria, Pertussis, Tetanus
C. Dengue, Pneumonia, TB
D. Diarrhoea, Pneumonia, Typhoid
✅ Correct Answer: B. Diphtheria, Pertussis, Tetanus
Q70. Oral polio vaccine is given through:
A. Injection
B. Mouth (drops)
C. Skin patches
D. Inhalation
✅ Correct Answer: B. Mouth (drops)
Q71. Which disease has been eradicated globally due to vaccination?
A. TB
B. Smallpox
C. Polio
D. Malaria
✅ Correct Answer: B. Smallpox
Q72. Antibodies are produced by which cells?
A. RBCs
B. WBCs (lymphocytes)
C. Platelets
D. Plasma
✅ Correct Answer: B. WBCs (lymphocytes)
Q73. Which vitamin deficiency lowers immunity?
A. Vitamin A
B. Vitamin B
C. Vitamin C
D. Vitamin D
✅ Correct Answer: C. Vitamin C
Q74. Which immunity is present from birth?
A. Acquired immunity
B. Innate immunity
C. Active immunity
D. Passive immunity
✅ Correct Answer: B. Innate immunity
Q75. Which one is the most cost-effective way of controlling infectious diseases?
A. Treatment by medicines
B. Vaccination and public health measures
C. Surgery
D. Isolation of patients
✅ Correct Answer: B. Vaccination and public health measures
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