Health is a state of complete physical, mental and social well-being, not only the absence of disease.
Important Questions Class 8 Science Chapter 3 help students revise health, diseases, immunity, vaccines, antibiotics and prevention.
Health affects how students learn, play, sleep, think and interact with others. Class 8 Science Chapter 3 explains that being healthy includes physical fitness, mental balance and social well-being. It also explains symptoms, signs, communicable diseases, non-communicable diseases, pathogens, immunity, vaccination, antibiotics and antibiotic resistance. Students should revise examples like common cold, tuberculosis, cholera, typhoid, malaria, dengue, diabetes and asthma carefully. These important questions follow the 2026-27 chapter content and help students practise definitions, differences, prevention steps, case-based reasoning and data interpretation.
Key Takeaways
- Health: WHO defines health as complete physical, mental and social well-being.
- Disease: A disease affects the normal working of the body or mind.
- Communicable Diseases: These diseases are caused by pathogens and can spread from person to person.
- Vaccines: Vaccines train the immune system to recognise and fight harmful germs.
Important Questions Class 8 Science Chapter 3 Structure 2026-27
| Question Type |
Marks |
Best Answer Style |
| Objective Type |
1 mark |
Term, disease type or correct option |
| Very Short Answer |
2 marks |
Direct definition with one example |
| Short Answer |
3 marks |
Cause, spread and prevention |
| Long Answer |
5 marks |
Explanation with examples |
| Case-Based |
4 marks |
Situation, reason and prevention |
Objective Type Questions from Important Questions Class 8 Science Chapter 3
Objective questions from this chapter usually test health, symptoms, signs, pathogens, disease types, immunity, vaccines and antibiotics. Students should learn examples and prevention terms clearly.
Q1. Health means:
- Only absence of fever
b. Complete physical, mental and social well-being
c. Only physical strength
d. Only eating more food
Answer: b. Complete physical, mental and social well-being
Health includes body, mind and social relationships.
Q2. A disease is a condition that affects:
- Only school performance
b. Normal working of the body or mind
c. Only height and weight
d. Only social life
Answer: b. Normal working of the body or mind
A disease can affect one or more organs or organ systems.
Q3. Pain and tiredness are examples of:
- Signs
b. Symptoms
c. Vaccines
d. Pathogens
Answer: b. Symptoms
Symptoms are what a person feels.
Q4. Fever and rash are examples of:
- Signs
b. Habits
c. Nutrients
d. Vaccines
Answer: a. Signs
Signs can be seen or measured by others.
Q5. Disease-causing organisms are called:
- Nutrients
b. Pathogens
c. Vaccines
d. Antibodies only
Answer: b. Pathogens
Bacteria, viruses, fungi, protozoa and worms can act as pathogens.
Q6. Diseases caused by pathogens and spreading from person to person are called:
- Non-communicable diseases
b. Communicable diseases
c. Deficiency diseases only
d. Lifestyle diseases only
Answer: b. Communicable diseases
Examples include flu, typhoid, dengue, chickenpox and COVID-19.
Q7. Which of the following is a non-communicable disease?
- Typhoid
b. Measles
c. Diabetes
d. Chickenpox
Answer: c. Diabetes
Diabetes does not spread from one person to another.
Q8. Common cold and influenza are caused by:
- Virus
b. Worms
c. Lack of iron
d. Excess sugar only
Answer: a. Virus
They mainly affect the respiratory tract.
Q9. Tuberculosis is caused by:
- Virus
b. Bacteria
c. Protozoa
d. Worms
Answer: b. Bacteria
Tuberculosis commonly affects the lungs.
Q10. Malaria is caused by:
- Protozoa
b. Virus
c. Bacteria
d. Lack of vitamins
Answer: a. Protozoa
Malaria spreads through mosquito vectors.
Q11. Dengue fever is transmitted by:
- Contaminated food only
b. Mosquitos
c. Dust only
d. Loud sound
Answer: b. Mosquitos
Dengue spreads through mosquito bites.
Q12. The natural ability of the body to fight diseases is called:
- Immunity
b. Infection
c. Pollution
d. Antibiotic resistance
Answer: a. Immunity
The immune system helps protect the body from harmful pathogens.
Q13. Vaccines are mainly used to:
- Treat all diseases after they occur
b. Prevent certain diseases
c. Replace food
d. Kill all body cells
Answer: b. Prevent certain diseases
Vaccines are preventive, not curative.
Q14. Antibiotics work against:
- Only bacterial infections
b. All viral infections
c. All lifestyle diseases
d. All injuries
Answer: a. Only bacterial infections
Antibiotics do not work against viruses.
Q15. Assertion: Antibiotics should be taken only when prescribed by a doctor.
Reason: Wrong or incomplete use can lead to antibiotic resistance.
- Both Assertion and Reason are true, and Reason explains Assertion
b. Both are true, but Reason does not explain Assertion
c. Assertion is true, Reason is false
d. Assertion is false, Reason is true
Answer: a. Both Assertion and Reason are true, and Reason explains Assertion
Misuse of antibiotics can make bacteria resistant to treatment.
Very Short Answer Questions from Class 8 Science Chapter 3 Important Questions
Very short answers from this chapter usually ask for definitions and examples. Write the direct answer first, then add one clear fact.
Q16. What is health according to WHO?
Health is a state of complete physical, mental and social well-being. It is not merely the absence of disease.
A healthy person can generally work efficiently and cope with difficult situations.
Q17. What is a disease?
A disease is a condition that affects the normal working of the body or mind. It may occur when one or more organs or organ systems do not function properly.
Q18. What is the difference between symptoms and signs?
Symptoms are what a person feels, such as pain, tiredness or dizziness.
Signs are what can be seen or measured, such as fever, rash, swelling or high blood pressure.
Q19. What are pathogens class 8 science?
Pathogens class 8 science means disease-causing organisms. Bacteria, viruses, fungi, worms and protozoa can cause diseases.
Q20. What are communicable diseases class 8?
Communicable diseases class 8 are diseases caused by pathogens that can spread from one person to another. Examples include common cold, flu, typhoid, dengue and chickenpox.
Q21. What are non communicable diseases class 8?
Non communicable diseases class 8 are diseases that do not spread from one person to another. Examples include diabetes, cancer, asthma and heart disease.
Q22. What is immunity class 8 science?
Immunity class 8 science means the natural ability of the body to fight diseases. The immune system helps protect the body from harmful pathogens.
Short Answer Questions from Health The Ultimate Treasure Class 8 Important Questions
Short answer questions from this chapter usually test disease causes, spread and prevention. Use examples from the chapter.
Q23. Why is health more than not falling sick?
Health is more than not falling sick because it includes physical, mental and social well-being.
A person may not have fever or infection but may still feel lonely, stressed or socially isolated. Good health means the person can work well, stay positive and adjust with others.
This is why health includes body, mind and relationships.
Q24. List five habits that help us stay healthy.
Five habits that help us stay healthy are:
- Eating a balanced diet.
- Maintaining personal hygiene.
- Exercising regularly.
- Getting enough sleep.
- Limiting screen time.
Yoga, meditation, clean surroundings and positive relationships also support health.
Q25. How does a clean environment help us stay healthy?
A clean environment reduces the chances of disease.
Clean air helps prevent breathing problems. Clean water prevents water-borne diseases. Clean surroundings reduce mosquito and fly breeding. A clean playground or home also supports better physical and mental well-being.
Thus, environment affects health directly.
Q26. How do communicable diseases spread?
Communicable diseases spread through different routes.
They may spread through air when an infected person coughs or sneezes. They can spread through contaminated food or water. Some spread through direct contact or shared personal items. Others spread through vectors like mosquitos and houseflies.
Understanding the route helps us prevent the disease.
Q27. Give examples of diseases spread through air.
Diseases spread through air include common cold, influenza, chickenpox, measles and tuberculosis.
These may spread when an infected person coughs, sneezes or releases droplets into the air. Covering the mouth and nose, wearing masks and maintaining hygiene can reduce spread.
Q28. Give examples of diseases spread through contaminated food and water.
Diseases spread through contaminated food and water include hepatitis A, cholera, typhoid and ascariasis.
These diseases can be prevented by drinking boiled water, eating properly cooked food, maintaining personal hygiene and following good sanitation habits.
Q29. How can we prevent mosquito-borne diseases?
Mosquito-borne diseases can be prevented by stopping mosquito breeding.
People should avoid stagnant water around homes, use mosquito nets and repellents, wear long-sleeved clothes and keep surroundings clean. These steps help prevent malaria and dengue.
Q30. Why are diabetes, cancer and asthma called non-communicable diseases?
Diabetes, cancer and asthma are called non-communicable diseases because they do not spread from one person to another.
They are not caused by pathogens. They are often linked to lifestyle, diet, environment, heredity or long-term body changes.
Long Answer Questions from Important Questions Class 8 Science Chapter 3
Long answer questions from this chapter usually ask for comparisons, prevention steps and explanations. Keep answers structured and example-based.
Q31. Differentiate between communicable and non-communicable diseases.
| Basis |
Communicable Diseases |
Non-Communicable Diseases |
| Cause |
Caused by pathogens |
Usually linked to lifestyle, diet, environment or deficiency |
| Spread |
Spread from person to person |
Do not spread from person to person |
| Examples |
Flu, typhoid, dengue, chickenpox |
Diabetes, asthma, cancer, heart disease |
| Prevention |
Hygiene, vaccination, safe food, vector control |
Healthy diet, exercise, sleep and regular check-ups |
| Treatment |
Depends on pathogen |
Long-term care and lifestyle changes may be needed |
Both types of diseases need prevention and timely care.
Q32. Explain common ways in which communicable diseases spread and how they can be prevented.
Communicable diseases are caused by pathogens and can spread in many ways.
- Air: Diseases like flu, common cold, measles and TB can spread through coughing or sneezing.
- Food and water: Cholera, typhoid and hepatitis A spread through contaminated food or water.
- Direct or indirect contact: Some diseases spread through touch or shared personal items.
- Vectors: Malaria and dengue spread through mosquitos.
Prevention includes washing hands, wearing masks in crowded places, drinking boiled water, eating clean food, using mosquito nets and avoiding sharing personal items.
Vaccination also prevents several serious diseases.
Q33. Explain vaccines class 8 science and their importance.
Vaccines class 8 science means preparations that train the immune system to recognise and fight specific germs.
Vaccines may contain weakened or dead pathogens, harmless parts of pathogens or instructions that help body cells make a harmless germ part. The immune system learns to recognise the germ and responds faster later.
Vaccines are preventive, not curative. They help prevent serious infections before they happen. Vaccines also reduce disease spread and protect people around us.
Examples include vaccines for polio, measles, tetanus and hepatitis.
Q34. Explain antibiotics class 8 science and antibiotic resistance.
Antibiotics class 8 science means medicines that kill or stop the growth of bacteria.
They work only against bacterial infections because they target bacterial cells. They do not work against viruses, protozoa or lifestyle diseases.
Antibiotic resistance class 8 means bacteria survive and multiply even when treated with an antibiotic that earlier killed them. This can happen when antibiotics are taken unnecessarily, in wrong doses or for incomplete duration.
To prevent resistance, antibiotics should be taken only when prescribed by a doctor and for the full recommended course.
Q35. How can communicable and non-communicable diseases be prevented?
Communicable diseases can be prevented by blocking the spread of pathogens.
We should wash hands regularly, cover the mouth while coughing, wear masks in crowded places, drink boiled water, eat clean food, avoid sharing personal items and control mosquito breeding.
Non-communicable diseases can be prevented by adopting a healthy lifestyle.
We should eat a balanced diet, reduce oily and sugary food, exercise regularly, sleep well, manage stress, avoid tobacco and alcohol and go for regular health check-ups.
Prevention is better than cure because it reduces illness, cost and long-term complications.
Case-Based Questions from Class 8 Science Health Important Questions
Case-based questions from this chapter usually describe a health situation. Identify the disease type, cause, spread and prevention.
Q36. Case Study: Flu outbreak in school
Several students in a school have fever, cough, sore throat and body ache. Some students still attend school while coughing and sneezing.
Q36(a). Which type of disease is flu?
Flu is a communicable disease.
It is caused by a virus and can spread from person to person.
Q36(b). How can flu spread in school?
Flu can spread through air when infected students cough or sneeze.
It can also spread through shared personal items or close contact.
Q36(c). What immediate steps should the school take?
The school should advise sick students to rest at home.
It should encourage handwashing, mask use, covering the mouth while coughing and cleaning shared surfaces.
Q36(d). How can a student respond kindly to a sick classmate?
The student can politely suggest resting, wearing a mask and informing a teacher.
This protects others without being rude or hurtful.
Q37. Case Study: Travel to a malaria-prone area
A family is travelling to a city where malaria cases are common during monsoon. They are advised to use mosquito nets and repellents.
Q37(a). What causes malaria?
Malaria is caused by a protozoan pathogen.
It is transmitted by mosquitos.
Q37(b). Why are mosquito nets useful?
Mosquito nets prevent mosquito bites during sleep.
This reduces the chance of malaria transmission.
Q37(c). What precautions should the family take?
They should use mosquito nets, repellents and long-sleeved clothes.
They should also avoid areas with stagnant water and follow health advisories.
Q37(d). What may happen if they ignore precautions?
They may get mosquito bites and develop malaria.
Ignoring advisories can increase infection risk.
Q38. Case Study: Antibiotics for cold
Saniya says antibiotics can cure any infection, including cold and flu. Her friend Vinita knows this is incorrect.
Q38(a). Why is Saniya’s statement incorrect?
Saniya’s statement is incorrect because antibiotics do not cure all infections.
They work only against bacterial infections.
Q38(b). Why should antibiotics not be taken for cold or flu?
Cold and flu are usually caused by viruses.
Antibiotics do not work against viruses.
Q38(c). What can happen if antibiotics are misused?
Misuse can lead to antibiotic resistance.
Resistant bacteria become harder to treat.
Q38(d). What should Vinita ask Saniya?
Vinita can ask, “Do antibiotics work against viruses or only bacteria?”
This question helps Saniya rethink her claim.
Data-Based Questions from Health The Ultimate Treasure Class 8 Important Questions
Data-based questions from this chapter often connect disease cases with season, environment and prevention. Give the trend first, then the reason.
Q39. A hospital reported dengue cases as follows: January 10, February 12, March 15, April 18, May 22, June 40, July 65, August 65, September 65, October 30, November 30, December 20. In which months were dengue cases highest?
The dengue cases were highest in July, August and September.
Each of these months recorded 65 cases.
Q40. Why might dengue cases rise during July, August and September?
Dengue cases may rise during these months because monsoon creates stagnant water.
Mosquitos breed in stagnant water. More mosquito breeding increases dengue transmission.
Q41. What preventive steps can reduce dengue before peak season?
Communities should remove stagnant water from coolers, pots, tyres and drains.
They should use mosquito nets, repellents and long-sleeved clothes. Local authorities should clean drains, spray mosquito-control measures and spread awareness before monsoon.
Diagram and Table-Based Questions from Important Questions Class 8 Science Chapter 3
Diagram and table-based questions from this chapter usually test classification and comparison. Keep examples accurate.
Q42. Make a table of diseases spread through air, food-water and insects.
| Mode of Spread |
Diseases |
Preventive Measures |
| Air |
Common cold, influenza, chickenpox, measles, TB |
Mask, hygiene, isolation, vaccination |
| Food and Water |
Hepatitis A, cholera, typhoid, ascariasis |
Boiled water, cooked food, sanitation |
| Insects |
Malaria, dengue |
Mosquito nets, repellents, no stagnant water |
The mode of spread tells us the correct prevention method.
Q43. Classify these diseases as communicable or non-communicable: cold and flu, typhoid, diabetes, asthma and chickenpox.
| Disease |
Type |
| Cold and flu |
Communicable |
| Typhoid |
Communicable |
| Diabetes |
Non-communicable |
| Asthma |
Non-communicable |
| Chickenpox |
Communicable |
Communicable diseases spread through pathogens, while non-communicable diseases do not spread person to person.
Q44. What should a school health campaign include?
A school health campaign should include messages on hygiene, vaccination, balanced diet, exercise, sleep, screen-time control and mental well-being.
It should also include disease prevention steps, such as handwashing, safe drinking water, mosquito control and avoiding tobacco, alcohol and addictive drugs.
A good campaign should address both communicable and non-communicable diseases.
Chapter-Wise Revision for Important Questions Class 8 Science Chapter 3
Important questions class 8 science chapter 3 should be revised in five parts: health, diseases, disease spread, prevention and treatment.
Start with the meaning of health. Remember that health includes physical, mental and social well-being.
Next, revise symptoms and signs class 8. Symptoms are felt by the person, while signs are seen or measured.
Then revise communicable diseases class 8 and non communicable diseases class 8. Focus on causes, examples and spread.
After that, revise immunity class 8 science and vaccines class 8 science. Vaccines train the immune system and help prevent serious infections.
Finally, revise antibiotics class 8 science and antibiotic resistance class 8. Antibiotics work against bacteria, but misuse can make bacteria resistant.
Class 8 Science Chapter List