CBSE Class 9 Biology Why Do We Fall Ill Worksheet Set B

Read and download free pdf of CBSE Class 9 Biology Why Do We Fall Ill Worksheet Set B. Students and teachers of Class 9 Biology can get free printable Worksheets for Class 9 Biology in PDF format prepared as per the latest syllabus and examination pattern in your schools. Standard 9 students should practice questions and answers given here for Biology in Grade 9 which will help them to improve your knowledge of all important chapters and its topics. Students should also download free pdf of Class 9 Biology Worksheets prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this academic year and solve important problems provided here with solutions on daily basis to get more score in school exams and tests

Why Do We Fall Ill Class 9 Biology Worksheet Pdf

Class 9 Biology students should refer to the following printable worksheet in Pdf for Why Do We Fall Ill in standard 9. This test paper with questions and answers for Grade 9 Biology will be very useful for exams and help you to score good marks

Class 9 Biology Worksheet for Why Do We Fall Ill


CBSE Class 9 Biology Worksheet - Why Do We Fall Ill (2)

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Q1. What is health?

Q2. Expand WHO.

Q3. What is disease?

Q4. How has WHO defined health?

Q5. Whom will you call disease free?

Q6. What do you mean by symptoms of a disease?

Q7. What is an acute disease?

Q8. Define chronic disease.

Q9. What is an infectious disease.?

Q10. Give one example each of diseases caused by bacteria and virus.

Q11. Expand HIV.

Q12. Name the target organ of Japanese encephalitis and AIDS virus.

Q13. Expand DPT.

Q14. What may be the symptoms of a disease when brain is infected?

Q15. Define vaccination.

Q16. Name any two modes of transmission of AIDS.

Q17. Name any two animals which transmit rabies to humans.

Q18. Give any two examples of viral diseases.

Q19. Name the disease in which:

a) a person fears from water b) yellowing of skin takes place

Q20. Name the causal organism as well as the vector of malaria.


Q1. Distinguish between acute and chronic diseases in two points.

Q2. Mention the type of causal organism of the following diseases:

T.B. , Malaria , Kala azar , measles

Q3. Which bacterium causes peptic ulcer? Who discovered it for the first time?

Q4. Mention any two protozoan diseases. Also name their causal organisms .

Q5. What is an antibiotic? Give 2 examples.

Q6. What is the principle of immunization?

Q7. Name any 2 diseases transmitted through vectors.

Q8. Why is it difficult to develop vaccines for some diseases?

Q9. Name such a vaccine , which saves the life of babies from three diseases.

Q10. What precautions would you take in your school to reduce incidence of infectious diseases?

Q11. Balanced diet is necessary for maintaining healthy body . Explain.

Q12. Our surrounding area should be free of stagnant water. Explain.

Q13. Why is AIDS considered a syndrome and not a disease?

Q14. Identify the target organ of :

a) hepatitis b) fits c) pneumonia d) fungus

Q15. Why do some children fall ill more frequently than others living in the same locality?


Q1. Describe the various community issues that influence health.

Q2. Explain various modes of transmission of infectious diseases.

Q3. Explain the various general ways of preventing diseases.

Q4. Write a note on the principle of treatment .

Q5. Why is immune system essential for our health?


 Exam Questions NCERT Class 9 Science Chapter 13 Why do we fall ill

Question. Which Vaccine was discovered for the first time and who discovered it?
Ans : Edward Jenner invented the vaccine for the first time and it was of smallpox.

Question. Why is making of anti-viral drugs more difficult than making anti-bacterial medicines?
Ans : Because viruses have very few biochemical mechanism of their own.

Question. State the principle of immunization.
Ans : Immune system responds against infectious microbes after detecting it first time. If this microbe again enter in body, immune system respond vigorously. This eliminate the infection more quickly than the first time. This is the principle of immunization.

Question. Many vaccines form the public health programme of childhood immunisation for preventing infectious disease. Name any two such diseases.
Ans : (i) Vaccine against measles. (ii) BCG vaccine against T.B.

Question. What is an epidemic disease? Which organ is affected if a person is suffering from jaundice?
Ans : An epidemic is the rapid and extensive spread of disease that affects many individuals simultaneously in a particular area. It is generally an infectious disease. Liver is affected if the person is suffering from jaundice.

Question. State two principles of treatment of a disease. Name the approaches generally adopted to treat infectious diseases.
Ans : There are two ways to treat an infectious disease :
(i) Reducing the effect of the disease.
(ii) Killing the microorganisms that act as infectious agents. There is two approaches to treat the infectious diseases. These are : (a) To reduce the effects of the disease. (b) To eliminate or kill the cause of the disease.

Question. What is inflammation? What are the symptoms and sign of inflammation?
Ans : It is the recruitment process by immune system in which immune system recruits many cells to the affected tissue to kill the disease causing germs. During this process, certain local effects such as swelling and pain and general effects such as fever may develop.

Question. Name the pathogens which can cause acne and sleeping sickness.
Ans : Acne – Staphylococci. Sleeping sickness – Trypanosoma.

Question. Name any four diseases transmitted through vectors.
Ans : Malaria, Dengue, Kala-azar and Plague.

Question. State giving reasons whether the following statements are correct or not :
(i) Our surrounding area should be free from stagnant water.
(ii) Staying clean is not necessary as long as you eat a balanced diet.
(iii) Social equality and harmony are necessary for good health.
Ans : (i) Yes, because stagnant water is the breeding place of mosquitoes which causes diseases like malaria, dengue, etc.
(ii) No, as balance diet is essential for a good health but hygiene is also important to remain disease free.
(iii) Yes, because health refers to a state of physical, mental and social well-being. Our social environment plays an important role in our individual health.

Question. How does public cleanliness affect our health?
Ans : Public cleanliness is important for our health. If someone is living in a filthy neighbourhood, he has a greater risk of being affected by some or the other epidemic.

Question. What do you understand by disease?
Ans : A condition in which the affected person is unable to carryout normal activities is termed as disease.

Question. What is the various dimensions of health?
Ans : Various dimensions of health is :
(i) Physical dimensions : Physical health implies perfect functioning of all the organs and systems of the body.
(ii) Mental dimensions : Mental health implies a state of balance and harmony between the individual and surrounding world.
(iii) Social dimensions : A person is socially healthy if he has a good job, a good house, a happy family, good neighbours and understanding friends.

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