Why Do We Fall Ill Part 2: MCQs (Q26–Q50)
🩺 Why Do We Fall Ill – Class 9 Science MCQs
Section 2: Infectious Agents, Means of Spread & Prevention (Q26–Q50)
Q26. The causative organism of malaria is:
A. Plasmodium
B. Anopheles mosquito
C. Trypanosoma
D. Bacteria
✅ Correct Answer: A. Plasmodium
Explanation:
- A. Correct, malaria is caused by Plasmodium protozoa.
- B. Wrong, Anopheles is only the vector.
- C. Trypanosoma causes sleeping sickness.
- D. Bacteria cause TB, cholera etc., not malaria.
Q27. Which organism causes tuberculosis (TB)?
A. Virus
B. Mycobacterium tuberculosis
C. Plasmodium
D. Fungus
✅ Correct Answer: B. Mycobacterium tuberculosis
Q28. Which disease is caused by a virus?
A. Typhoid
B. AIDS
C. Malaria
D. TB
✅ Correct Answer: B. AIDS
Q29. Which of the following spreads through sexual contact?
A. Malaria
B. AIDS
C. Cholera
D. Dengue
✅ Correct Answer: B. AIDS
Q30. Which of the following is spread by Aedes mosquito?
A. Malaria
B. Dengue
C. TB
D. Cholera
✅ Correct Answer: B. Dengue
Q31. Common cold is caused by:
A. Influenza virus
B. Rhinovirus
C. Bacteria
D. Fungi
✅ Correct Answer: B. Rhinovirus
Q32. Which is NOT a vector-borne disease?
A. Malaria
B. Dengue
C. TB
D. Sleeping sickness
✅ Correct Answer: C. TB
Q33. Which organism causes sleeping sickness?
A. Plasmodium
B. Trypanosoma
C. Wuchereria
D. Leishmania
✅ Correct Answer: B. Trypanosoma
Q34. Kala-azar is caused by:
A. Leishmania
B. Trypanosoma
C. Wuchereria
D. Plasmodium
✅ Correct Answer: A. Leishmania
Q35. Which disease is caused by Wuchereria?
A. Filariasis (Elephantiasis)
B. Malaria
C. Dengue
D. Typhoid
✅ Correct Answer: A. Filariasis (Elephantiasis)
Q36. Which of these is a bacterial disease?
A. Cholera
B. AIDS
C. Dengue
D. Kala-azar
✅ Correct Answer: A. Cholera
Q37. Means of spread of cholera:
A. Contaminated food and water
B. Mosquito bites
C. Air
D. Sexual contact
✅ Correct Answer: A. Contaminated food and water
Q38. Which organ is mainly affected by Mycobacterium tuberculosis?
A. Liver
B. Kidney
C. Lungs
D. Brain
✅ Correct Answer: C. Lungs
Q39. The best method to prevent malaria is:
A. Vaccination
B. Killing mosquitoes & using nets
C. Antibiotics
D. Drinking clean water
✅ Correct Answer: B. Killing mosquitoes & using nets
Q40. Hepatitis B affects which organ?
A. Lungs
B. Liver
C. Kidney
D. Brain
✅ Correct Answer: B. Liver
Q41. Which disease can spread from mother to child?
A. AIDS
B. Malaria
C. Cholera
D. Dengue
✅ Correct Answer: A. AIDS
Q42. Rabies is caused by:
A. Virus
B. Bacteria
C. Protozoa
D. Fungus
✅ Correct Answer: A. Virus
Q43. Which is the carrier of Kala-azar?
A. Female Anopheles mosquito
B. Male Aedes mosquito
C. Sandfly
D. Housefly
✅ Correct Answer: C. Sandfly
Q44. Pneumonia is caused by:
A. Bacteria
B. Virus
C. Protozoa
D. Fungus
✅ Correct Answer: A. Bacteria
Q45. AIDS virus weakens which system of body?
A. Nervous system
B. Digestive system
C. Immune system
D. Circulatory system
✅ Correct Answer: C. Immune system
Q46. Polio is caused by:
A. Bacteria
B. Virus
C. Protozoa
D. Fungus
✅ Correct Answer: B. Virus
Q47. Which of these is NOT a means of spreading infectious diseases?
A. Air
B. Water
C. Vectors
D. Genetics
✅ Correct Answer: D. Genetics
Q48. Which of these prevents spread of water-borne diseases?
A. Using mosquito nets
B. Vaccination
C. Drinking boiled/clean water
D. Covering mouth while sneezing
✅ Correct Answer: C. Drinking boiled/clean water
Q49. Which method is NOT useful in preventing infectious diseases?
A. Proper sanitation
B. Good nutrition
C. Isolation of patients
D. Vaccination
✅ Correct Answer: B. Good nutrition
Explanation:
- Nutrition improves immunity but does NOT prevent spread of pathogens directly.
Q50. Vaccination provides:
A. Artificial passive immunity
B. Artificial active immunity
C. Natural immunity
D. No immunity
✅ Correct Answer: B. Artificial active immunity
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