NCERT Solutions for Class 9th: Ch 13 Why Do We Fall Ill Science

In text Questions

Page No: 178

1. State any two conditions essential for good health.

Answer

Two conditions that are essential for good health are: 
→ Proper nutrition and a blanced diet
→ Good Social environment.

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

Answer

Two conditions essential for being disease-free are: 
→ Person should take balance diet. 
→ Personal and community hygiene. 

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

Answer

To some extent they are the same, because if the conditions that are essential for good health are maintained, then automatically the chances of getting a disease will be minimized. But at the same time, we can say that they are different because being health or good health means physical, mental and social well-being while being disease-free means not suffering from a particular disease.

Page No: 180

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

Common symptoms which indicate sickness are:
→ Headache
→ Cough
→ Dysentery 

If only one of these symptoms is present, we usually do not visit a doctor. This is because such symptoms do not have much effect on our general health and ability to work. However, if a person is experiencing these symptoms for quite sometime, then he needs to visit a doctor for proper treatment.

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.

Answer

Jaundice is a disease that can cause long-term effects on our health. It is a chronic disease that lasts for a long period of time. Jaundice does not spread rapidly, but it develops slowly over a period of time.

Page No: 187

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

Answer

When we are sick the normal body functions get disturbed. In such situation food that is easily digestible and contains adequate nutrients are required for the speedy recovery. Thus bland and nourishing food is given during sickness.

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

Answer

The different modes of transmission of infectious diseases are:
→ Through Air: Certain disease-causing micro-organisms are expelled in air by coughing, sneezing, talking, etc. These micro-organisms can travel through dust particles or water droplets in air to reach other people. For example, tuberculosis, pneumonia, etc. spread through air.
→ Through Water: Sometimes causal micro-organisms get mixed with drinking water and spread water borne diseases. Cholera for example is water borne disease.
→ Through Sexual Contact: Sexual act between two people can lead to the transfer of diseases such as syphilis, gonorrhoea, AIDS, etc.
→ Through Vectors: Certain diseases spread by animals called vectors. For example mosquitoes spread malaria.

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

Answer

Precautions to reduce incidence of infectious diseases are:
→ Staying away from the infected person.
→ Covering mouth or nose while coughing or sneezing to prevent the spread of disease.
→ Drinking safe water.
→ Keeping the school environment clean to prevent multiplication vectors.

4. What is immunization?

Answer

Immunizationis defined as protection of the body from communicable diseases by administration of some agent that mimics the microbe.

5. What are the immunization 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 centre are DPT (Diphtheria, Pertusis, and Tetanus), polio vaccine, hepatitis B, MMR (Measles, Mumps, and Rubella), jaundice, typhoid, etc.
Of all these diseases, jaundice and typhoid are major health problems.

Page No: 188

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

The following precautions must be taken by a doctor/ nurse/ health-worker:
→ Wearing a mask when in contact with a diseased person.
→ Keeping yourself covered while moving around an infected place.
→ Drinking safe water.
→ Eating healthy and nutritious food.
→ Ensuring proper cleanliness and personal hygiene.

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) The baby is sick can be determined by his/her behavioural changes such as constant crying of baby, improper intake of food, frequent mood changes, etc.

(b) The sickness is determined by symptoms or indications that can be seen in the baby. The symptoms include vomiting, fever, loose motion, paleness in the body, 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.

Answer

(c)A person is more likely to fall sick when she is on a four day fast after recovering from malaria and is taking care of someone who is suffering from chicken pox. This is because she is fasting during recovery, and her immune system is so weak that it is not able to protect its own body from any foreign infection. If she is taking care of someone suffering from chicken pox, then she has more chances of getting infected from chicken pox virus and will get sick again with this 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)You are more likely to fall sick when your friend is suffering from measles. This is because measles is highly contagious and can easily spread through respiration i.e., through air. Thus, if your friend is suffering from measles, stay away from him otherwise you might easily get infected with the disease.