Why Do We Fall Ill?| NCERT Solutions| Class 9

NCERT Solutions of  Chapter: Why Do We Fall Ill?. NCERT Solutions along with worksheets and notes for Class 9.

Page 178

(1) State any two conditions essential for good health.

Ans(i) Health is a state of being well enough to function well physically, mentally and socially.

(ii) The health of all organisms depends on their surroundings or their environment. We should be healthy to face environmental difficulties like natural calamities (as flood, cyclone etc.). Our surroundings should be clean to keep us healthy.


(2) Sate ant two conditions essential for being free of disease.

Ans- (i) Good nourished food is essential for good immune system which keeps us free of disease.

(ii) Clean drinking water is necessary for free of disease.


(3) Are the answers to the above questions necessarily the same or different? Why?

Ans – The answers of above both questions are different. A person who is free of disease may have poor health. We know that health is related to our physical, mental and social state. But free of disease means that a person does not have any disease but can have bad health.


Page 180

(1) List any three reasons why you would think that you are sick and ought to see a doctor. If only one of these symptoms were present, would you still go to the doctor?

Why or why not?

Ans- The three reasons which make me sick and ought to see a doctor are listed below –

(i) High fever

(ii) Headache

(iii) Vomiting

If only one of these symptoms were present I will not go to doctor immediately. If I do not get relief then I will go to doctor.


(2) In which of the following case do you think the long – term effects on your health are likely to be most unpleasant?

  • If you get jaundice.
  • If you get lice.
  • If you get acne.



  • “If I get jaundice”, it will leave long – term effects on my health because jaundice attacks on liver that will make me very weak and I will not be able to digest food. Therefore, jaundice will harm my digestive system and liver.
  • “If I get lice’, it will not harm my health except I will be itching my head all time.
  • “If I get acne”, it will not harm my health except my face will not look good.

Hence, jaundice will leave the most unpleasant long – term effects on my health.


Page 186

(1) Why are we normally advised to take bland and nourishing food when we are sick?

Ans- We are normally advised to take bland and nourishing food when we are sick because bland food is easily digestible and nourished food for functioning and strengthening of our immune system.


(2) What are the different means by which infectious diseases are spread?

AnsMeans of spreading infectious diseases –

(i) Communicable diseases can be spared through air by droplets of infected persons.

Eg:- Cold, cough etc.

(ii) Communicable diseases can be spared by touch of infected persons.

Eg:- Cold, viral fever, corona etc.

(iii) Diseases can be spread by drinking infected water.

Eg:- If excreta of an infected person (cholera)get mixed in drinking water and water is used by healthy person. Then person will e infected with disease.

(iv) These diseases can be communicated through sexual act.


These diseases never transmitted with casual contact as handshake, touch etc. but can be transmitted to babies by their mothers at the time of delivery.

(v) The animals which carry infecting agents from a sick person to another potential host are called vectors.

Eg:- mosquitoes, flies etc.

These vectors spread malaria, dengue etc.


(3) What precautions can you take in your school to reduce the incidence of infectious diseases?

Ans- Precautions which we can take in our school to reduce the incidence of infectious diseases-

(i) We can prevent exposure to air borne microbes by providing not overcrowded classes.

(ii) We can prevent exposure to water borne microbes by providing safe drinking water after treating the water to kill any microbes.

(iii) We can prevent exposure to vector borne diseases by providing clean environment.


(4) What is immunisation?

Ans- The process in which an individual body becomes healthy by vaccination to protect against previous microbes is called immunisation.

When our immune system first sees an infectious microbe, it responds against it and remembers it specifically. Next time same microbes or its close relative enter our body, the immune system fight against microbes with greater physical strength which is provided by vaccination. This process is called immunisation.

Eg:- Small pox, measles, tetanus, polio, diphtheria and many more diseases have vaccination. These vaccinations protect us with infecting microbes from turning into actual disease.


(5) What are the immunisation programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?

Ans- Vaccination for various diseases like measles, small pox, BCG, drops for polio and many more diseases are available at the nearest health center of my locality.

Now a days, corona is the major health problem because we do not have vaccination for this virus base disease till now.



(1) How many times did you fall ill in the last one year? What were the illness?

(a) Think of one change you could make in your habits in order to avoid any of/most of the above illnesses.

(b) Think of one change you would wish for in your surroundings in order to avoid any of/ most of the above illnesses.

Ans- I suffered from fever and loose motions once in a year at separate times.

(a) I stopped eating outside specially gol gappe.

(b) I wish to reduce air pollution which will be boon for asthma patients. I also wish no water logging to keep away mosquitoes.


(2) A doctor/ nurse/health – worker is exposed to more sick people than others in the community. Find out how she/ he avoids getting sick herself/ himself.

Ans- A doctor/ nurse/health – worker should use mask and disposable gloves before examining patient to protect themselves from diseases. They should also sanitise their hand before touching patients.


(3) Conduct a survey in your neighbourhood to find out what the three most common diseases are. Suggest three steps that could be taken by your local authorities to bring down the incidence of these diseases.


The three common diseases in my neighbourhood are

(i) Polio

Steps taken by local authorities

(a) Polio drops are essential for every kid below five year.

(b) Government health worker provide medicines door to door for kids of below five year.

(c) Local authorities set camps for polio drops. Date of the date is announced very early before the camp.

(ii) Dengue

Steps taken by local authorities

(a) Local authorities advertise how to keep clean surroundings, no water logging, change water in cooler etc. to aware the people.

(b) Government workers come door to door to check about water logging. They also check coolers to find out larva of dengue.

(iii) Malaria

Steps taken by local authorities

(a) Local authorities’ spray DDT powder in surroundings.

(b) They suggest people to keep their surroundings clean and no water logging.


(4) A baby is not able to tell her/his caretakers that she/he is sick. What would help us to find out

(a) that the baby is sick?

(b) what is the sickness?

Ans –(a) Fever, vomiting, crying, not taking milk are few symptoms that show that baby is not well.

(b) The sickness should be detected by the doctor while we take baby to him.


(5) Under which of the following conditions is a person most likely to fail sick?

(a) when she is recovering from malaria.

(b) when she has recovered from malaria and is taking care of someone suffering from chicken – pox.

(c) when she is on a four – day fast after recovering from malaria and is taking care of someone suffering from chicken – pox.



(a) She herself recovered from malaria recently. Therefore, her immune system is weak.

(b) She is taking care of someone suffering from chicken – pox and recovered from malaria. Chicken – pox is a communicable disease. Therefore, she can be infected with chicken – pox.

(c) She is on a four – day fast after recovered malaria and taking care of chicken – pox. Therefore, she is not taking nourished food and taking care of a person who has communicable disease chicken – pox. As a result her immune system and physical health is very weak and she is prone to fall sick.


(6) Under which of the following conditions are you most likely to fall sick?

(a) when you are taking examinations.

(b) when you have traveled by bus and train for two days.

(c) when your friend is suffering from measles.


Ans- (a) It may possible that my examination for articular disease come positive.

(b) It may possible that I got infection from any of passenger.

(c) If I come in contact with my friend who is suffering from measles, I will get infection because measles is a contagious disease.

Therefore, I am likely to fall sick in above given condition is (c).

Helping Topics

Why do We Fall Ill?

Worksheet Class 9



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