NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall Ill ?

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.

Answer : Falling ill varies from person to person. Some people fall ill many times in an year, while some do not fall ill at all. Habits of balanced diet and exercises must be facilitated. Personal hygiene and hygiene of surrounding play an important role for persons health.

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 : Following practices should be followed by doctor / nurse/ health worker-

• Wear a mask while communicating with a diseased person.
• Keep body covered while moving from infected place.
• Maintain cleanliness and personal hygiene.
• Eat nutritious food and drink safe water.

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 : Most common diseases are – Typhoid, jaundice, tuberculosis, hairfall, acne, etc. Steps to be taken by local authorities to bring down these diseases are –

• Make safe drinking water available
• Markets should include fresh vegetable and fruits
• Proper garbage and sewage disposal.

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?

Answer: a) Baby is sick can be determined by behavioural changes like crying, food intake, etc. b) Sickness of baby can be determined by the symptoms like cold, fever, vomiting, loose motions, etc.

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?

Answer: c) A person is more likely to fall sick when she is on four day fasting after recovering from malaria and is taking care of someone suffering from chicken pox. This is due to fasting during the recovery from malaria, also, the immune system is weak which is unable to protect body from other infection. If she is taking care of person suffering from chicken pox, it is likely to catch infection and get sick again with the 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 : (c) when your friend is suffering from measles.

Measles is highly contagious disease. It easily spreads through air. Therefore, if your friend is suffering from measles then stay away, to keep yourself protected.

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Download free NCERT textbook class 9 Science – Chapter 13 Why Do We Fall Ill