NCERT Class 9 Science Chapter 13 Why do we Fall Ill?

Chapter 13 Why do we Fall Ill?

Intext Question and Answers
Question 1: State any two conditions essential for good health.
Answer: Two conditions essential for good health are:
• A person should have better health facilities to deal with health problems.
• Better social environment.

Question 2: State any two conditions essential for being free of disease.
Answer: Two conditions essential for being free of disease are:
• Eating nutritious food.
• Living in a healthy and hygienic environment.

Question 3: Are the answers to the above questions necessarily the same or different? Why?
Answer: The answers to the above questions are different because a person may be free of disease but not be good mentally, socially and economically.

Question 4: 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: Headache, stomach pain, vomiting etc. are the symptoms that makes us feel that we are sick and need to visit a doctor. It will be difficult for us to predict the kind of disease and we end up visiting the doctor so that the disease can be treated with proper medication before the disease’s condition worsens. However, if only one of these symptoms is present, we usually don’t visit a doctor. This is because such symptoms don’t have much effect on our health and ability to do work. However, if a person is experiencing these symptoms quite regularly, then that person needs to visit the doctor for proper treatment before that symptoms turns into any disease.

Question 5: 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: If a person gets jaundice, it will be most unpleasant as it is a chronic-disease and cause long term effects on our health. Lice and acne can be cured using medicated shampoo and proper cleanliness respectively.

Question 6: Why are we normally advised to take bland and nourishing food when we are sick?
Answer: When we are sick our body is weak. By consuming bland and nourishing food we can get the nutrients and the energy quickly to fight the disease. Oil and spices will be difficult to digest as our metabolic system is weak.

Question 7: What are the different means by which infectious diseases are spread?
Answer:
• Through air: This occurs through the little droplets thrown out by an infected person (i.e. by cough or sneeze). Example: pneumonia etc.
• Through water: This occurs if the excrete of a person who is suffering from an infectious gut disease (like cholera etc.) gets mixed up with water used by people living nearby. Example: diarrhoea etc.
• Through physical contact: Certain disease such as AIDS can spread via blood to blood contact during blood transfusion or during pregnancy.
• Through  vectors: These diseases spread through vectors, like dogs, mosquitoes etc. Example: Rabies etc.

Question 8: What precautions can you take in your school to reduce the incidence of infectious diseases?
Answer: Some of the precautions that we can take in our school to reduce the incidence of infectious diseases are:
• Trying to stay away from students who are infected.
• Covering mouth and nose while coughing and sneezing.
• Keeping the school environment clean so that there are no vectors for the disease.

Question 9: What is immunisation?
Answer: Immunisation is a process of protecting body from communicable diseases against an agent.

Question 10: 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 centers are Measles, Mumps, and Rubella (MMR), polio vaccine, jaundice, Diptheria, Pertusis, and Tetanus (DPT), typhoid, hepatitis B etc. From the above typhoid and jaundice are the major health problems.

Exercise Questions
Question 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: I had fever last year. I had severe cold and cough.
• Eating a balanced diet.
• Keeping surroundings clean.

Question 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:
• Keeping their mouths covered with a mask while in contact with an infected person.
• Eating healthy and nutritious diet.
• Ensuring proper hygiene and cleanliness.

Question 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: Three most common diseases are dengue, typhoid and jaundice. Steps that should be taken by our local authorities to bring down the incidence of the disease are:
• Proper disposal of garbage.
• Proper maintenance of open sewage system and canals.
• Ensuring the supply of safe drinking water.

Question 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) Sickness can be determined by the behaviour changes of the baby.
b) Sickness can be symptoms or indication (which include vomiting, fever, loose motions, paleness in body etc.

Question 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: In condition ‘c)’ a person is more likely to fall sick. This is because she is fasting during recovery from malaria and her immune system will be so weak that it will not be able to protect her own body from any foreign infection. If she is taking care of someone who is suffering from chicken-pox, then she has more chances of getting infected from chicken-pox virus and will get sick again with this disease.

Question 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: A person is more likely to fall sick in condition ‘c)’. This is because measles is a highly communicable diseases and can easily spread through air. Thus, if your friend is suffering from measles, stay away from him/her otherwise you might easily get infected with the disease.