NCERT solution for class 9|| Science || Chapter 13 - Why do we fall ill

 NCERT solutions  >Class 9 > Science 

Chapter 13- Why do we fall ill  

Page number 178 

Q1. State any two conditions essential for good health ? 

Answer -  Two condition essential for good health are 

• A healthy person is free from all kind of disease 
• A person should be physically mentally and socially fit is called healthy .

Q2. State any two conditions essential for being free of disease ? 

Answer - Two conditions essential for being free of disease are 

• To keep personal hygiene and cleanliness 
• To get sufficient and balanced food to keep body free from disease 

Q3 . Are the answers to the above questions necessarily the same or different why ?

Answer-  Both question above mentions have different answer because by the term of health mean mental, physical and social health while free of disease is only related to physical health

Page number 180 

Q4. 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? 

Answer - The common symptoms are 

Headache ,High fever and diarrhoea any of them symptoms is observed then the person should be immediately contact the doctor

Q5. In which of the following case do you think the long term effect on your health are likely to be most unpleasant 

If you get jaundice 

 If you get lice

 If you get acne why  ? 

Answer - In jaundice because it is a chronic disease which may stay for a long time.

Page number 187 

Q6. Why are we normally advised to take bland and nourishing food when we are sick ? 

Answer - We are normally advised to take bland and nourishing food when we are sick because during infection the immunity power of the body decreases and complete nourishment is required for faster recovery

Q7. What are the different means by which infectious diseases are spread ? 

Answer - In following ways that different infectious diseases are spread 

By air - It is also called air borne disease it carries bacteria and viruses after sneezing and coughing the microbes sprayed into the air and enter to the healthy person body .eg common cold , TB etc.

By water- It is also called water borne diseases the microbes enter in body by drinking polluted and contaminated water Eg. Cholera , typhoid etc.  

By Sexual Contact - Some disease can be transmitted by sexual contact eg. AIDS , syphilis etc 

By vector - Some organisms  spread disease by caring pathogen from one place to another place called vector eg. Mosquito are vectors that carry pathogens like protozoa

Q8. What precautions can you take in your school to reduce the incidence of infectious disease ? 

Answer - The precaution that one can take in school to reduce the infectious diseases are 

• Washing hands before eating food 
• By using handkerchief while coughing and sneezing 
• Preventing accumulation of water in and around the school 
• Keeping the toilet clean 
• Avoiding the use of uncovered food and fruits 
• Keeping ground and classroom clean  
• By preventing gathering of people

Q9. What is a immunisation ? 

Answer - Immunity session is the method of preparing memory cells in immune system in this method the weekend that microbes of disease are injected to the body such that they develop memory of WBC's and do not cause disease in future eg. 

Q10. What are the new session programme available at the nearest health centre in your locality which of these diseases are the major health problem in your area ? 

Answer - Some immunisation programmes 

• BCG vaccine against TB 
• Vaccine against smallpox 
• Polio vaccine to prevent polio 
• TAB vaccine for typhoid  
• Hepatitis vaccine 
• Vaccine against measles

Exercise 

Q1. How many times did you fall ill in the last one year what were the illnesses ?  

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

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

Answer - This is very from person to person 

a) It is also varies from disease to disease but normally change the daily routine 

b) Change in surrounding to prevent the accumulation of garbage and dirty water and keep the surrounding clean

Q2. 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

Answer - Doctor nurses health workers for sick more frequently than others they can keep themselves safe by 

• Cover their mouth with mask 
• Cleaning their hands after checking up the patient 
• Avoid  direct physical contact with patient .
• Take balance diet 
• The take care of hygiene

Q3. 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 being down the incidence of these diseases ?

Answer - Three most common diseases are tuberculosis malaria dysentery 

Precautions 

• Proper disposal of sewage 
• Regular cleaning of sewage line and proper exist of sewage water 
• Keep the surrounding and environment clean 
• Destroy the mosquitoes  from stagnant water 
• Insuring supply of safe drinking water  

Q4. Baby is not able to tell her/ his care takers that she /he is sick what would help us to find out

 a) That the baby is sick  

b) What's is the sickness 

Answer - Some particular symptoms of cough dysentery etc. are indicates that the child is sick 

• Each disease has its own symptoms which tells us about the disease hit change the  behaviour of baby
• The sickness is determined by the symptoms that can be seen in baby and the symptoms like vomiting loose motion , fever etc.

Q5. Under which of the following conditions a person most likely to fall sick ? 

a) When she is recovering from malaria 

b) When she has recovered from malaria and is taking care of someone suffering from chickenpox 

c) When she is on a four day fast after recovering from malaria and it's taking care of someone suffering from chickenpox why ? 

Answer - When after recovering back from malaria she is taking care of a person suffering from smallpox 

Because due to unavailability of sufficient and balanced diet and  weakened immune system

Q6. Under which of the following conditions are you most likely to fall sick 

a) When you are taking examinations 

b) When you have travelled by bus and train for 2 days 

c) When your friend is suffering from measles why .

Answer-  c)  when your friend is suffering from measles 

Reason - Measles is air born  disease when my friend cough or sneeze the small drops from his mouth containing microbes mix in the air and that microbes may be carried away by the air and it is it getting chance to infected The other healthy person in this case I may fall serverly seek