Class 9 Science Chapter 13 Why do we fall ill

NCERT Solutions for Class 9 Science Chapter 13

NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill.
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Question 1. State any two conditions for good health 
Answer: Two conditions essential for good health are:
State of physical, mental and social well-being.
Better surroundings or -environment.

Question 2. State any two conditions essential for being free of disease.
Answer. The two conditions essential for being free of disease are:
Personal and -domestic .hygiene.
Clean environment and surroundings

Question 3. Are the answers to the above questions necessarily the same or different ? Why ?
Answer: The answer to the above questions are different because a person may be free of disease but his mental, social or economical health may not be good.

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Question 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) cold and 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.
Even in case of single symptom one needs to go to the doctor to get proper treatment.

Question 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: In the above cases, lice and acne are acute problems of our health which can be cured in short duration. But jaundice is the disease that can have most unpleasant effect on our health as it affects the most important organ of our body i.e., liver. This disease is a chronic one.

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Question 1. Why are we normally advised to take bland and nourishing food when we are sick?
Answer: We are advised to take bland and nourishing food when we are sick because our body needs energy to release cells to overcome the infection, the wear and tear of body organ. The nourishing food provides nutrients to our body that will further provide energy and make new cells. No spices in the food makes its digestion process faster, does not release acids in the body that can interfere in the treatment and cure.

Question 2. What are the different means by which infectious diseases are spread?
Answer: The different means by which infectious diseases spread are:
(a) 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.
(b) Through food and water: When one eats/drinks contaminated food/water, that contains bacteria, virus, worm etc. it can cause diseases like cholera typhoid, hepatitis.
(c) Through contact: Many diseases spread by contact of infected person with the healthy person. Example, fungal infections, skin diseases, scabies etc.
(d) By sexual contact: Many diseases can be transmitted, example, syphilis, AIDS.
(e) By body fluids: Fluids like blood, semen, mother’s milk, when infected,
can also cause diseases. Example, AIDS.
(f) 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.

Question 3. What precautions can you take in your school to reduce the incidence of infectious diseases?
Answer: The precautions that one can take in school to reduce the incidence of infectious diseases are
(a) By using handkerchief while coughing sneezing.
(b) Washing hands before eating tiffins.
(c) Staying at home if anyone suffers from infectious diseases.
(d) Getting vaccinated before the infection affects.
(e) Keeping the school surroundings clean, checking for stagnant water.

Question 4. What is immunisation?
Answer: When the body attains immunity against any disease, due to vaccination. This process is called immunisation.

Question 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?
Answer: The immunization programmes available at the nearest health care centres are:
  1. Child immunization programme starts from 0 to 12 years.
  2. Polio eradication programme
  3. H1N1 screening programme
In major areas tuberculosis cases are reported in a large number which is a major concern.

NCERT Solutions

CBSE Educational Study Material.