SEBA Class 9 Science: Why Do We Fall Ill?
IN-TEXT QUESTION
1. State any two conditions essential for good health.
Answer: Two conditions essential for good health are:
1. Having better surroundings or environment, like clean drinking water and proper sanitation.
2. Having social equality and harmony for living a happy and peaceful life
2. State any two conditions essential for being free of disease.
Answer: Two conditions essential for being free of disease are:
1. Having proper nourishment and sufficient food.
2. Having a clean environment, safe drinking water and proper sanitation
3. Are the answers to the above questions necessarily the same or different? Why?
Answer: The answers are different. Simply being free of disease does not mean being healthy. Health is a state of complete physical, mental and social well-being, while disease-free only means not suffering from any particular disease.
IN-TEXT 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: Common symptoms which show that a person is sick are:
(i) Headache
(ii) Cough
(iii) Loose motions
Even if one symptom is present, I would still go to the doctor because a single symptom can also be the sign of a disease. If treatment is delayed, it may turn into something serious. For example, a headache may sometimes indicate a dangerous illness
2. In which of the following cases 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: The long-term effects on health will be most unpleasant if a person gets jaundice. This is because jaundice is a chronic disease which takes a long time to be cured. Moreover, it affects the whole body and it also takes time for the person to become completely healthy again. On the other hand, lice and acne do not cause such long-lasting effects.
IN-TEXT 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 it is easy to digest and provides all the necessary nutrients. This helps the body to conserve energy, recover faster, and fight the infection more effectively.
2. What are the different means by which infectious diseases are spread?
Answer: Infection-causing microbes can spread from a sick person to others in the following ways:
1. Through air: When an infected person sneezes or coughs, tiny droplets carrying microbes spread in the air. Another person may breathe them in and get diseases like common cold and pneumonia.
2. Through water: If drinking water becomes contaminated with germs, it spreads diseases such as cholera when used.
3. Through sexual contact: Diseases like syphilis and AIDS are transmitted from one person to another during sexual contact.
4. Through animals (vectors): Some animals act as carriers of germs. For example, the female Anopheles mosquito spreads malaria from one person to another.
3. What precautions can you take in your school to reduce the incidence of infectious diseases?
Answer: To reduce the incidence of infectious diseases in school, the following precautions can be taken:
1. Keeping classrooms clean and airy to avoid overcrowding.
2. Providing safe drinking water to prevent water-borne diseases.
3. Maintaining proper sanitation in toilets and surroundings.
4. Making sure there is no stagnant water where mosquitoes can grow.
5. Encouraging students to wash hands before meals and after using toilets.
4. What is immunisation?
Answer: Immunisation is the process by which the immune system of our body is prepared in advance to fight against a particular infection. In this method, a substance that mimics the microbe is put into the body. It does not cause the actual disease but makes the immune system remember and respond quickly if the real microbe enters in the future. This protects the person from that disease.
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 immunisation programme available at the nearest health centre in our locality includes:
(i) BCG vaccine against tuberculosis.
(ii) Polio drops against polio.
(iii) Vaccination against chicken pox.
(iv) Vaccination against hepatitis.
(v) Immunisation against measles.
The major health problems in our area are:
(i) Hepatitis.
(ii) Chicken pox.
(iii) Tuberculosis (TB).
(iv) Tetanus.
EXERCISE QUESTIONS
1. 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: A doctor, nurse or health-worker avoids getting sick by taking proper precautions. They maintain personal hygiene, wash hands regularly, use masks, gloves and sterilised instruments, and follow safety guidelines while treating patients. They are also protected through immunisation against common infectious diseases. These measures reduce the chances of infection even though they remain close to sick people.
Note: Sterilised means making an object completely free from germs or microbes.
2. 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) Symptoms that help us to know the baby is sick are:
(i) Continuous crying and restlessness
(ii) Improper intake of food and change in body temperature
(b) The kind of sickness can be understood from organ-specific and tissue-specific symptoms. For example, yellowness of skin and eyes indicates diseases like jaundice or hepatitis.
3. 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: A person is most likely to fall sick in condition (c) – when she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox. This is because after malaria, the body is already weak, and fasting makes it even more weak. At the same time, close contact with a person having chicken-pox increases the chance of infection. Therefore, in this condition the risk of falling sick is the highest.
4. 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: I am most likely to fall sick when my friend is suffering from measles. This is because measles is an infectious disease and it spreads from an infected person to others. On the other hand, taking examinations or travelling may cause tiredness but they do not directly spread infectious diseases.