Why Do We Fall Ill Practice Questions

Class 9 · Science · 3472 free MCQs with instant results and detailed explanations.

3472

Total

1060

Easy

1719

Medium

693

Hard

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Topics in Why Do We Fall Ill

Types of Diseases 867

Prevention 861

Infectious Diseases 858

Health and Disease 886

Sample Questions from Why Do We Fall Ill

Here are 10 sample questions. Start a quiz to get randomized questions with scoring.

Easy

What is a disease caused by a lack of essential nutrients in the diet?

A. Scurvy

B. Influenza

C. Malaria

D. Tuberculosis

Show Answer & Explanation

Correct Answer: A

Scurvy is caused by a deficiency of vitamin C, indicating that it is a nutritional disease.

Easy

Which of the following is a communicable disease?

A. Diabetes

B. AIDS

C. Cancer

D. Hypertension

Show Answer & Explanation

Correct Answer: B

AIDS is caused by the HIV virus and can be transmitted from one person to another.

Easy

Which of the following is NOT a symptom of malaria?

A. Fever

B. Chills

C. Headache

D. Rash

Show Answer & Explanation

Correct Answer: D

Rash is generally not associated with malaria; fever, chills, and headache are common symptoms.

Medium

What is the primary cause of infectious diseases?

A. Bacteria

B. Vitamins

C. Exercise

D. Water

Show Answer & Explanation

Correct Answer: A

Infectious diseases are primarily caused by pathogens like bacteria, viruses, fungi, and parasites.

Medium

Which of the following is NOT a vector for disease transmission?

A. Mosquito

B. Housefly

C. Dog

D. Dust

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Correct Answer: D

Dust does not transmit diseases; it may carry allergens but is not a biological vector like mosquitoes or houseflies.

Medium

Which of the following diseases is caused by a virus?

A. Tuberculosis

B. Malaria

C. HIV

D. Cholera

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Correct Answer: C

HIV is caused by the Human Immunodeficiency Virus, while the others are caused by bacteria or parasites.

Medium

What term describes the ability of an organism to resist disease?

A. Immunity

B. Contagion

C. Infection

D. Pathology

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Correct Answer: A

Immunity is the ability of an organism to resist infection and disease, often developed through exposure or vaccination.

Hard

Which of the following diseases is primarily caused by a deficiency in the immune system, making individuals more susceptible to infections?

A. Tuberculosis

B. Diabetes Mellitus

C. Acquired Immunodeficiency Syndrome (AIDS)

D. Common Cold

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Correct Answer: C

AIDS is caused by the HIV virus, which attacks the immune system, leading to a significantly reduced ability to fight off infections. In contrast, tuberculosis is caused by a bacterium, diabetes is a metabolic disorder, and the common cold is caused by various viruses but does not indicate a deficiency in the immune system.

Hard

Which of the following best describes a communicable disease?

A. A disease that can be transmitted from one person to another

B. A disease that is hereditary

C. A disease that occurs due to environmental factors

D. A disease that does not spread between individuals

Show Answer & Explanation

Correct Answer: A

Communicable diseases are caused by pathogens that can be spread from one individual to another, unlike hereditary or environmental diseases.

Q10

Hard

Which of the following is NOT a vector for disease transmission?

A. Mosquitoes

B. Houseflies

C. Water

D. Rats

Show Answer & Explanation

Correct Answer: C

Water is a medium for disease but not a vector; vectors actively carry and transmit pathogens.

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Why Do We Fall Ill — Class 9 Science Practice Questions Online

This page contains 3472 practice MCQs for the chapter Why Do We Fall Ill in Class 9 Science. The questions are organized by difficulty — 1060 easy, 1719 medium, 693 hard — so you can choose the right level for your preparation.

Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 4 topics, giving you comprehensive coverage of the entire chapter.