Why do we fall ill Class 9 Important Questions

Given below are the Why do we fall ill Important Questions and worksheet for Class 9 Biology
a.Multiple choice questions
b.Match the column
c. Very Short answer
d. Short Answer type
e. Long answer questions

Multiple choice questions

Question 1.
Which one of the following is not a viral disease?
(a) Dengue
(b) AIDS
(c) Typhoid
(d) Influenza
Question 2.
Which one of the following is not a bacterial disease?
(a) Cholera
(b) Tuberculosis
(c) Anthrax
(d) Influenza
Question 3.
Which one of the following disease is not transmitted by mosquito?
(a) Brain fever
(b) Malaria
(c) Typhoid
(d) Dengue
Question 4.
Which one of the following disease is caused by bacteria?
(a) Typhoid
(b) Anthrax
(c) Tuberculosis
(d) Malaria
Question 5.
Which one of the following diseases is caused by protozoans?
(a) Malaria
(b) Influenza
(c) AIDS
(d) Cholera


1. c
2. d
3. c
4. d
5. a

Match the column

Question 6.
Classify the following diseases as infectious or non-infectious.


(a) infectious
(b) infectious
(c) infectious
(d) non-infectious
(e) non-infectious
(f) infectious
(g) non-infectious

Very Short Answer type

Question 7.
Write the causing agent of peptic ulcer?


Helicobactor pylori

Question 8.
Write the full form of AIDS ?


Acquired Immuno Deficiency Syndrome

Question 9.
Give two example of Antibiotics


Penicillin and

Question 10.
Name any two groups of microorganisms from which antibiotics can be extracted?


bacteria (Neomycin) and fungi (Penicillin)

Question 11.
Write the name of two protozoan diseases with their causing agent?



Question 12.
Who give the control for peptic ulcer?


Marshall and Warren

Question 13.
What are antibiotics?


Antibiotic is a chemical substance that kill bacteria, secreted by microorganisms which can kill the pathogens.

Question 14.
Why do penicillin is not effective against common cold?


Penicillin is an Antiboitics and Antibiotics generally block the biosynthetic pathways and they block these pathways of the microbes/bacteria. However, viruses have very few biochemical mechanisms of their own and hence are unaffected by antibiotics

Question 15.
What is health?


Health has been described as the state of complete physical, mental and social well being. According to the World Health Organization (WHO), health is a state of complete physical, mental and social well-being and not merely an absence of disease or infirmity.

Question 16.
Write the principle of treatment of diseases?


There are two principle of treatment
(i) reduce the effects of the disease . we can provide treatment that will reduce the symptoms. The symptoms are usually because of inflammation
(ii) kill the cause of the disease. we can use medicines that kill microbes

Question 17.
How AIDS disease is spread?
Question 18.
Write the principle of immunization?


We ‘fool’ the immune system into developing a memory for a particular infection by putting something, that mimics the microbe we want to vaccinate against, into the body.
This does not actually cause the disease but this would prevent any subsequent exposure to the infecting microbe from turning into actual disease

Question 19.
What are different means of spread?
Question 20.
What are aims of pulse polio immunization program?
Question 21.
What are limitations of prevention of diseases?
Question 22.
What are communicable diseases?


Those diseases which are passed on from one person to another in various ways through air, water, food, physical contact and insects

Question 23.
What is syndrome?
Question 24.
What is interferon?
Question 25.
Write the symptoms of AIDS and how AIDS can be prevented?
Question 26.
Write the control of peptic ulcer?
Question 27.
Why a person suffering from AIDS cannot fight even small infections?


AIDS is caused by HIV which damages the immune system of the person suffering from it. Thus, the person cannot fight even small infections.

Question 28.
Why female Anopheles mosquito feeds on human body?


They need nutritious food in the form of blood in order to be able to lay mature eggs.

Question 29.
Write a brief note on peptic ulcers?
Question 30.
Mention any two preventive measures given to the patient after a rabid animal bites?

Long Answer Questions

Question 31.
‘Prevention is better than cure’. Justify the statement with three reasons?
Question 32.
Explain the process of inflammation? Mention the local effects and the general effects of inflammation?
Question 33.
With the diagram only, depict the common methods of transmission of diseases?
Question 34.
(i)Mention any three basic conditions required for good health?
(ii)Why are we normally advised to take blend and nourishing food when we are sick?
Question 35.
During a health check up camp in a school, the doctor talked about prevention of diseases. Which main points will you share with your friends on “prevention of diseases is more desirable than its successful treatment”?
Question 36.
Differentiate between communicable and non-communicable diseases?
Question 37.
‘Over crowded and poorly ventilated housing is a major factor in the spread of airborne diseases’. Explain the statement and support your answer with diagram also?
Question 38.
Arun is having headache and fever. He takes some pills to bring down the fever and headache before going to the doctor. What is this type of treatment called? How can we reduce the effects of the diseases? What is the limitation of this type of treatment? What is the possible remedy of these diseases?
Question 39.
AIDS is a syndrome which damages body’s immune system.
a.Name the causative agent of the disease.
b.List four ways through which the AIDS pathogen enter the body of a healthy person?


This Important Questions for Why do we fall ill for Class 9 Science(Biology) with answers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.

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