NCERT Solutions for Class 9th Science

Chapter 13 - WHY DO WE FALL ILL

(Complete Downloadable Chapter Solution PDF file is at the bottom of the page)

 

Q.1      State any two conditions essential for good health.

Ans    Health means a state of physical, mental and social well-being and for an individual it depends on his/her physical surroundings and his/her economic status. The conditions essential for good health are:

            1) Clean physical environment with efficient public cleanliness system

            2) Social equality and harmony

            3) Good economic conditions and jobs

Q.2      State any two conditions essential for being free of disease.

Ans     The conditions essential for being free of disease are:

            1) Proper nutrition and balanced diet

            2) Personal and community hygiene

Q.3      Are the answers to the above questions necessarily the same or different? Why?

Ans    No, the answers to Q.1 and Q.2 need not necessarily be the same. This is because a disease free state is not same as being healthy. Health means a state of physical, mental and social well-being i.e. ability of an individual to realise his/her full potential whereas being disease free means not suffering from a particular disease. Individuals can have poor health without having any identifiable disease. Further, health is related to societies and communities, whereas having a disease is related to individual sufferers. Hence, conditions for good health and being free of disease can be same or different.

Q.4      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?

Q.5      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.

Why?

Q.6      Why are we normally advised to take bland and nourishing food when we are sick?

Q.7      What are the different means by which infectious diseases are spread?

Q.8      What precautions can you take in your school to reduce the incidence of infectious diseases?

Q.9      What is immunisation?

Ans   Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. It makes the immune system to develop a memory for a particular infection by putting something, that mimics the microbe we want to vaccinate against, into the body. This would prevent any subsequent exposure to the infecting microbe from turning into actual disease.

Q.10      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?

 

EXERCISES

 

Q.1      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 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.

Q.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.

Q.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.

Ans    The three most common diseases are malaria, diarrhoea and jaundice. These diseases can be controlled by following the given below measures:

            1) Clean drinking water supply and arrangements of proper sanitation system.

         2) Cleaning of surroundings which includes providing proper means for garbage disposal, not allowing stagnant water to accumulate etc.

          3) Monitoring of proper implementation of immunisation programmes and creating awareness among people regarding healthy lifestyle and prevention of diseases.

Q.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?

Q.5      Under which of the following conditions is 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 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. Why?

Ans    A person is most likely to fall sick when she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox because due to fasting i.e. lack of proper and sufficient food, her immune system gets affected and will not be able to function properly. Therefore, the person may easily get infected from the virus of chicken pox.

Q.6      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 two days.

(c) when your friend is suffering from measles. Why?

Ans      You are most likely to fall sick when your friend is suffering from measles. This is because measles is is a highly contagious respiratory infection that's caused by a virus. So, when you visit your friend, you are most likely to get affected by the infectious microbes of measles.