CBSE Class 9 Biology Why Do We Fall Ill Worksheet

CBSE Class 9 Biology Worksheet - Why Do We Fall Ill (3)

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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?

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