NCERT Solutions for Class 9 Science - Chapter 13 : Why do we fall ill

NCERT Solution - Chapter 13 : Why do we fall ill, Class 9,Science

Questions & Answers

1. How many of these ways we can think of are events that would occur when the disaster is actually happening ?

Ans. (i) Disease caused due to shortage of drinking water.

(ii) Health affected by the shortage of food.

(iii) Diseases caused to due sanitary problems.

(iv) Health affected due to unavailabilities of shelter.

2. How many of these health-related events would happen long after the actual disaster, but would still be because of the disaster ?

Ans. (i) Diseases caused due to accumulation of dirty water e.g., malaria.

(ii) Spread of water borne diseases like cholera, dysentry etc.

(iii) Diseases caused due to rotting things in the debris.

3. Why would one effect on health fall into the first group, and why would another fall into the second group ?

Ans. This is because the disease or the effect on health which are placed in the first group are caused immediately after the disaster takes place. But, the effect or diseases in the second group, however are ultimately due to disaster, but takes time to take place.

4. List any three reasons why you would think that you are sick and ought to seek a doctor. If only one of these symptoms were present, would you still go to the doctor ? Why or why not ?

Ans. Some general symptoms -

(i) Headache (ii) Cough (iii) Dysentery

If any of the above symptoms is observed, the person should immediately contact the doctor.

Cause : Any of the symptoms can be the cause of disease. If these are ignored, the person may have to face a dangerous situation.

5. In which of the following case do you time the long-term effects on your health are likely to be most unpleasant?

(i) If you get jaundice (ii) If you get lice. (iii) If you get a acne.

Ans. In Jaundice because, it is a chronic disease which may stay for a long-time.

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

Ans. During infection, the immune power of the body decreases. So, to maintain the immune power we are suggested to take sufficient and easily digestible food.

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

Ans. Following are the means of spread of diseases -

(i) By air : By sneezing and coughing, the microbes spread into the air and enter the body of healthy man.

(ii) By water : The microbes enter our body by drinking polluted and contaminated water.

(iii) By sexual contact : some disease like AIDS, spread by sexual contact with infected person.

(iv) By vectors : Some organisms like female anopheles mosquito also work as the vector of disease causing agent and hence spread diseases.

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

Ans. (i) By preventing gathering of people.

(ii) By making available clean and fresh drinking water.

(iii) By keeping ground and class rooms clean.

(iv) By using handkerchief to cover mouth while sneezing or coughing.

(v) By preventing accumulation of water in and around the school.

(vi) By using vaccines and immunisation

(vii) By keeping the toilet clean.

(viii) By avoiding the use of uncovered food and fruits.

9. What is immunisation ?

Ans. The process of developing immune power in the body to fight against the diseases is called immunisation.

10. 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 ?

Ans. (a) Some particular symptoms e.g., cough, cold, dysentery, etc. Indicate that child is sick.

(b) (i) Every disease has its own particular symptoms which tell us about the disease.

(ii) By carrying tests in the laboratory, the disease can be diagnosed.

11. 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. (c) When she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox.

Reason : (a) due to unavailability of sufficient and balanced diet and weakened immune system.

12. 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. (c) When my friend is suffering from measles.

Reason : In this condition, I will frequently visit my friends address. Measles is an airborne disease. When my friend coughs or sneezes, small drops from his mouth containing microbes mix in the air. The microbes may be carried away by air. So, the chance of getting infected increases. Hence, in this case I may fall severely sick.