NCERT Solutions Class 9 Science
The NCERT Solutions in English Language for Class 9 Science Chapter – 13 (Why Do We Fall Ill?) has been provided here to help the students in solving the questions from this exercise.
Chapter – 13 (Why Do We Fall Ill?)
Questions
1. State any two conditions essential for good health.
Answer – Two conditions essential for good health are:
1. State of physical, mental and social well-being.
2. Better surroundings or environment.
2. State any two conditions essential for being free of disease.
Answer – Two conditions essential for being free of disease are listed below:
1. Maintaining personal and public hygiene.
2. Clean environment and surroundings.
3. Are the answers to the above questions necessarily the same or different? Why?
Answer – The answers are not same all the time. Because the meaning of health varies from person to person.
Questions
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?
Answer – The 3 reasons why one would think that he is sick are –
1. Headache
2. Cough
3. Loose motions
This indicates that there may be a disease but does not indicate what the disease is. So one would still visit the doctor for the treatment and to know the cause of above symptom.
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. Why?
Answer – Lice and acne will not cause long lasting effects on our body. But in case of jaundice, there will be severe long lasting effects. For example:
(i) High temperature, headache and joint pains.
(ii) Feeling of nausea and vomiting.
(iii) Initiating rashes. The patient will suffer from poor health and will recover by taking complete bed rest for sometime.
Questions
1. Why are we normally advised to take bland and nourishing food when we are sick?
Answer – In case of illness, the normal functions of the body get disturbed. So, a nourishing food is required which is easily digestible and contains all the nutrients. Therefore, bland and nourishing food is advised to take during sickness.
2. What are the different means by which infectious diseases are spread?
Answer – The different means by which infectious diseases spread are:
- Through air – They are also called air-borne diseases. The air carries bacteria, virus and the diseases that can be caused are: common cold, influenza, tuberculosis etc.
- Through food and water – When one eats drinks contaminated food/water, that contains bacteria, virus, worm etc. it can cause diseases like cholera, diarrhea, typhoid, amebiasis, hepatitis, gastroenteritis etc.
- Trough contact – Many diseases spread by contact of infected person with the healthy person, Example, fungal infections, skin diseases, scabies etc.
- By sexual contact – Many diseases can be transmitted, example, syphilis, AIDS.
- By body fluids – Fluids like blood, semen, mother’s milk, when infected, can also cause diseases. Example, AIDS.
- Vectors – The organism that spreads a disease by carrying pathogens from one place to another is called vector. Example, mosquitoes are vectors that carry pathogens like protozoa.
3. What precautions can you take in your school to reduce the incidence of infectious diseases?
Answer – To prevent the incidence of infectious diseases in school following precautions can be taken:
1. Avoid contact of students suffering from air borne diseases like common cold, cough, eye, flu, etc.
2. By checking the availability of clean drinking water in school.
3. Clean surroundings in school will not allow the growth and multiplication of vectors.
4. Starting childhood immunisation programe in schools.
4. What is immunisation?
Answer – The method to boost our immune system with the help of vaccines that help the body to fight against infectious diseases is called immunisation.
5. What are the immunisation programs available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?
Answer – The following immunisation programme is available at the nearest health centre in our locality:
1. Immunisation for infants – DPT, BCG, polio, measles and MMR.
2. For children – Typhoid, TT, DT, smallpox and TAB.
3. For pregnant women— TT and hepatitis B.
The diseases like typhoid, polio, and measles are the major health problems in our locality.
Exercise
1. How many times did you fall ill in the last 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.
Answer – I had fallen ill twice in the past year. The illnesses were malaria and viral fever.
(a) Changes that I would like to make in my habits in order to avoid any more illnesses are as follows:
1. Having a bath daily.
2. Keeping the house, especially kitchen, clean in order to avoid creating a breeding place for the mosquitoes.
3. Having a proper balanced diet.
(b) Changes that I would like to make in my surroundings in order to avoid any more illnesses are as follows:
1. To prevent accumulation of garbage in the building/society.
2. To keep the society clean and dumping the waste in garbage bins provided.
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.
Answer – A doctor/nurse/health worker when exposed to sick people they keep their nose and mouth covered, take care of hygiene, wash hands with soap before drinking water or eating food. They use mask, gloves, etc to avoid the direct contact with the person suffering from infectious diseases.
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.
Answer – The following three are the most common diseases in any neighbourhood:
Cold and cough, loose motions, and malaria. Some of the preventive measures that can be taken are as follows:
(a) By drinking fresh, uncontaminated, and clean water.
(b) By maintaining hygienic sanitary conditions.
(c) By educating people about various preventive measures with the help of posters and pamphlets.
4. A baby is not able to tell her caretakers that she is sick. What would help us to find out
(a) that the baby is sick?
(b) what is the sickness?
Answer –
(a) Symptoms that help us to find that baby is sick, are
(i) Continuous crying and restlessness of the child.
(ii) Improper intake of food and body temperature.
(b) Kind of sickness can be known by certain organ-specific and tissue-specific symptoms e.g., yellowness of skin and eyes indicate the jaundice and hepatitis.
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 chickenpox.
(c) When she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken pox. Why?
Answer – A person is most likely to fall sick in (c) condition because malaria attack has caused large scale destruction of her blood cells so she is weak and anemic. Then she is on a four-day fast so is not getting proper and sufficient food which further decreases the functioning of her immune system and lastly chickenpox is a communicable and contagious disease.
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?
Answer – I will be most likely to fall sick when my friend is suffering from measles and I come in contact with him because measles is contagious disease and also spreads by droplet infection.
